The following is a list of unnamed Starfleet personnel who served in the sciences division aboard Deep Space 9.
Defiant officer 1 []

Aboard the Defiant
This sciences officer worked at a console on the aft bridge of the Defiant in 2372 during the negotiations with the Karemma in the Gamma Quadrant. During the attack of two Jem'Hadar fighters, his console exploded and he was thrown across the bridge. (DS9: "Starship Down")
Defiant officer 2 []
This sciences officer manned a side station on the bridge of the Defiant in 2372 when the ship met with the Karemma in the Gamma Quadrant and was attacked by two Jem'Hadar fighters. Her console exploded and Ensign Carson later checked her pulse, confirmed her death. (DS9: "Starship Down")
Medical officer 1 []

A medical officer
This medical officer was one of the few Starfleet officers who remained on the station when Bajorans took control of Deep Space 9 in early 2370. (DS9: "The Siege")
The same year, he passed by one of the station's airlocks, adjacent to the Replimat, as Proka Migdal and Rugal are met by Zolan as they departed their transport. (DS9: "Cardassians")
Later that year, while off duty, he had a drink at Quark's, shortly before he visited Club Martus. (DS9: "Rivals")
He passed the Replimat when Kor introduced Jadzia Dax to Koloth (DS9: "Blood Oath") and was talking to several civilians on the Promenade a few days later. (DS9: "The Maquis, Part II")
He passed the infirmary when Chief O'Brien stepped into the location and was later present in Quark's when Elim Garak collapsed. (DS9: "The Wire")
He listened to Quark when the Ferengi told about his glorious fight against Kozak and how he killed him. Later, he joined others in the bar for a drink. (DS9: "The House of Quark")

At the helm of the Defiant
In 2371 he was part of the bridge crew aboard the USS Defiant when they discovered the planet Meridian. He worked on the aft bridge when the planet suddenly appeared. When the crew investigated the dimensional shifts of the planet and its inhabitants, he manned the helm aboard the Defiant. Later he was back in the aft section, sitting at the table and also manned a side station. (DS9: "Meridian")
He participated in the dabo game when the brawl between the Romulans and the Klingon Intelligence officers started. Later he visited a shop on the Promenade. (DS9: "Visionary")
He visited Quark's and watched a game of darts between Jadzia Dax and Miles O'Brien. (DS9: "Shakaar")
He was among the crewmembers aboard the Defiant who were secured in their quarters when a Changeling saboteur took control of the ship. (DS9: "The Adversary")

During Bashir's briefing
He visited Quark's bar during the shore leave of dozens of Klingon officers aboard the station. A short time later, he went through the airlock from the same transport used by Lieutenant commander Worf for his arrival on the station. Off duty, he was a guest at Quark's during Worf's first visit to the bar and his beat-up of Drex. He was back on duty and passed Worf and Odo on the upper level of the Promenade when the two had a talk about loyalty. He was back at Quark's when Miles O'Brien introduced Worf to Kira, Dax, and Bashir. He boarded the Defiant for its mission to rescue the members of the Detapa Council. Back aboard the station, he visited Quark's bar again while Quark and Elim Garak talked about the future and the Federation and moved out of the bar when the station was put on a red alert. He was briefed by Julian Bashir in the Infirmary regarding the medical needs during the Klingon attack but a short time later, he was among the civilians on the Promenade evacuated into safe spaces. (DS9: "The Way of the Warrior")
In an alternate timeline in 2372, he attended the memorial service for Benjamin Sisko on the Promenade. (DS9: "The Visitor")
Off duty, he visited Quark's and was talking to a Bajoran deputy near the dabo table while Worf observed Regana Tosh. (DS9: "Hippocratic Oath")
He sat at the bar in Quark's when Dax performed a magical trick on Quark. A short time later, he was on duty at Ops when Dax went into the captain's office and Sisko told her about the arriving Trill scientists. Later, he was again at Quark's when Kira and Bashir spoke with Quark about Dax's past. (DS9: "Rejoined")
Together with a Bajoran woman he sat outside of Quark's on the upper level of the Promenade when Kira Nerys introduced Tora Ziyal to Odo. (DS9: "Return to Grace")
In 2372, he took the payment from the striking employees of Quark's and agreed not to visit the establishment. (DS9: "Bar Association")
Along with Garak and Tora Ziyal, he used the turbolift in 2372. (DS9: "For the Cause")
He was a patron at Quark's when Brunt closed the bar and took all property away from Quark. (DS9: "Body Parts")
He was present on the Promenade during Gowron's speech in 2372. (DS9: "Broken Link")
He stood at the entrance of Quark's on the upper level of the Promenade and talked to a civilian when Captain Sisko and Miles O'Brien passed him. (DS9: "Call to Arms")

Working at Starbase 375
Temporarily stationed at Starbase 375, he was one of the officers who studied the captured Jem'Hadar ship when Admiral Ross informed Sisko about his next assignment. (DS9: "A Time to Stand")
He served aboard the Defiant during the war between the Dominion and the Federation. He was present when Captain Sisko performed a ritual, he placed a discharged phaser array power cell on a rack at the mess hall of the Defiant. Later, he worked on the Defiant during its successful mission in destroying a Dominion facility near the Argolis Cluster. (DS9: "Behind the Lines")
He was among the Starfleet personnel who returned to Deep Space 9 after the Dominion lost the battle against the Federation. He was talking to several of the Bajorans and civilians who awaited their return on the Promenade. (DS9: "Sacrifice of Angels")
He left Quark's and was talking to another man. They stopped their talk when Kira and Odo had their first kiss on the Promenade. (DS9: "His Way")
He visited Quark's when the Vulcan Captain Solok challenged Captain Sisko for a baseball game (DS9: "Take Me Out to the Holosuite") and when Sarina Douglas was brought aboard the station and watched her playing dabo, hosted by dabo girl M'Pella. (DS9: "Chrysalis")
He was at the Replimat while Chief O'Brien and Nog had a discussion about the captain's desk. (DS9: "Treachery, Faith and the Great River")
He visited Quark's Bar again when the Klingon Kor asked Worf for a favor. (DS9: "Once More Unto the Breach")
He left a transport which arrived at Deep Space 9 and was missing Miles O'Brien. (DS9: "Prodigal Daughter")
He passed Odo and the Changeling Laas on the Promenade and witnessed the following fight between Laas and two Klingons in which one of the Klingons was killed by Laas. (DS9: "Chimera")
He visited Quark's several times in 2375 and participated in dabo games. (DS9: "Afterimage", "Penumbra", "Strange Bedfellows")
He was having a drink in the Replimat and later listened the speech of Grand Nagus Zek in Quark's. (DS9: "The Dogs of War")
Medical officer 2 []
This Starfleet officer served in the sciences division on board Deep Space 9.
He went to the Replimat and was talking to a Bajoran woman while Major Kira and Odo were talking about Odo's ability to eat. He then walked away but came back later while Tiron was talking to Kira and Odo. He later passed Tiron at the bar in Quark's and was also in Quark's when Major Kira entered and Quark announced her as his one millionth customer. While Kira and Odo were talking about Quark in the security office, he passed the office and went to a turbolift on the Promenade. He later visited along with a female civilian Quark's again, he entered at the entrance of the second level and passed Quark and Tiron on their way to the holosuites. He later left Quark's along with a female command officer. They passed Odo and Major Kira who witnessed an angry Tiron shouting at Quark. (DS9: "Meridian")
He stood near the dartboard at Quark's and watched a game of darts between Jadzia Dax and Miles O'Brien. (DS9: "Shakaar")
He was among the crewmembers aboard the Defiant who were secured in their quarters when a Changeling saboteur took over the control of the ship. (DS9: "The Adversary")
He was on duty in sickbay after Rom became unconscious and assisted Dr. Bashir in his treatment. (DS9: "Bar Association")
He was on duty at Ops when Captain Sisko and Jadzia Dax returned from a meeting at Starfleet Command in 2373. (DS9: "Apocalypse Rising")
He was on duty at Ops when Odo told Captain Sisko about his "solid" injuries in Sisko's office. (DS9: "Nor the Battle to the Strong")
He worked at Ops in 2373 while an auction took place at the station. (DS9: "In the Cards")
He was among the medical Starfleet personnel who were equipped with an emergency bag in in the infirmary when Captain Sisko called for battle stations due to the forthcoming attack of the Dominion on the station. A short time later, he was working at the master table in Ops during the attack and was among the Starfleet personnel who boarded the Defiant when Starfleet abandoned Deep Space 9. (DS9: "Call to Arms")
Medical officer 3 []

A medical officer
This medical officer was on duty and working in the aft section of the bridge aboard the Defiant in 2372 when it rescued Kasidy Yates freighter, the SS Xhosa, from a Klingon search party. He was also present on the bridge during the rescue mission for the members of the Detapa Council and the battle with the Klingons. Later, he was among the personnel who tested the blood of the council members in sickbay aboard the Defiant to make sure they were no Changelings. (DS9: "The Way of the Warrior")
He treated Captain Sisko and his concussion on the bridge of the Defiant after Sisko was wounded during the attack of two Jem'Hadar fighters. (DS9: "Starship Down")
Nurse 1 []

A female officer
This female medical officer was working on the science station on Ops when Michael Eddington was forced to load the neural patterns of Sisko, Dax, Worf, Kira, and O'Brien into the station's computer systems. She watched the transport of the senior staff from aboard the USS Orinoco and the following malfunction and remained on duty on Ops until the patterns were brought back by using the systems aboard the Defiant. (DS9: "Our Man Bashir")
She was reading a PADD in the infirmary after Kurn tried to end his life and let himself be shot by a Boslic captain. Later, she was also on duty at the infirmary and assisted Doctor Bashir in re-programming Kurn and give him a new identity as Rodek. (DS9: "Sons of Mogh")
Nurse 2 []
This Starfleet nurse served aboard the Defiant while in orbit of Gaia. She assisted Doctor Bashir placing Odo in stasis and treating Major Kira in the sickbay. (DS9: "Children of Time")
She was present when Julian Bashir and Miles O'Brien woke up and the neural link to Luther Sloan's mind was disconnected. She assisted Miles O'Brien to sit up. (DS9: "Extreme Measures")
Nurse 3 []

At Ops in 2370
This nurse assisted Doctor Julian Bashir in helping Li Nalas out of the airlock after he was brought to Deep Space 9 following his rescue from Cardassia IV. When it was learned that Li had taken a phaser hit, she and Bashir held him steady as Dax beamed them to the infirmary. (DS9: "The Homecoming")
She was among the Starfleet personnel during Sisko's briefing in Ops shortly before the Bajoran military tried to take over control of the station. (DS9: "The Siege")
She visited Quark's bar while Pel made some business opportunities to Quark. Later, she passed the Replimat on the Promenade when Pel told Jadzia Dax that she is female. (DS9: "Rules of Acquisition")
Later that year, she was enjoying the music played at Quark's by Varani while sitting next to Morn, eventually hugging Morn and resting her chin on his shoulder as she listened. (DS9: "Sanctuary")
Nurse 4 []
This nurse assisted Doctor Julian Bashir in preparing Captain Benjamin Sisko for neuropolaric induction surgery, following his exposure to a harmful Prophet-induced vision, in 2373. (DS9: "Rapture")
This ensign was among the crewmembers who were evacuated from the habitat ring following an explosion in Miles O'Brien's quarters. She passed Major Kira. (DS9: "The Darkness and the Light")
She was working in the infirmary and preparing medical kits for the forthcoming attack of the Dominion while Jake Sisko assisted in giving out these medkits. (DS9: "Call to Arms")
She was among the guests at the wedding of Jadzia Dax and Worf. (DS9: "You Are Cordially Invited")
Nurse 5[]
- See: Illusion nurse 001
Nurse 6 []

In the Infirmary
This female officer manned a side station on the bridge of the Defiant during the rescue mission for the members of the Detapa Council and during the Klingon attack. (DS9: "The Way of the Warrior")
In an alternate timeline of 2372, she attended the memorial service for Benjamin Sisko on the Promenade. A few months later she visited Quark's and talked to a woman while Nog tried to cheer up Jake Sisko with a visit to the holosuite. She was on duty in the Infirmary and handed Doctor Bashir a PADD when Bashir, Dax, and O'Brien tried to rescue Benjamin Sisko after he re-appeared on Deep Space 9. (DS9: "The Visitor")
Nurse 7 []
This female officer was on duty aboard the Defiant in 2372 and performed blood screenings on the members of the Cardassian Detapa Council after they were rescued from aboard the Prakesh. Back on Deep Space 9, she was among the medical personnel in the Infirmary who were briefed by Doctor Julian Bashir shortly before the Klingon attack on the station. (DS9: "The Way of the Warrior")
In an alternate timeline, a few months after the death of Benjamin Sisko, she was off duty when she walked behind Major Kira and Worf on the upper level of the Promenade. (DS9: "The Visitor")
Off duty she attended the reception for the Trill scientists Lenara Kahn, Bejal Otner, and Hanor Pren. Back on duty she talked to a lieutenant on the upper level of the Promenade when she passed Jadzia Dax who watched Lenara Kahn leave Deep Space 9. (DS9: "Rejoined")
She assisted Doctor Bashir in guiding the wounded crewmembers aboard the Defiant off the sickbay and deck two following an attack by two Jem'Hadar fighters. She went behind the bulkhead before Bashir sealed it. Back aboard the station, she was off duty and stood in the background of Quark#s when she watched Karemma Minister Hanok playing his first game of dabo. (DS9: "Starship Down")
Sao Paulo officer []

A sciences officer
This Starfleet officer served aboard the USS Sao Paulo in 2375.
He attended the official ceremony on the bridge in which Admiral William Ross gave Captain Sisko the command of the starship. He left the bridge shortly before Ross told Sisko that another point of interest was on the PADD he gave the captain, the name change from Sao Paulo to USS Defiant. (DS9: "The Dogs of War")
Sciences officer 1 []

A sciences officer
This sciences officer was wounded during the Dominion attack on Deep Space 9 in 2373. An operations lieutenant assisted him boarding the Defiant when Captain Sisko ordered the evacuation of Deep Space 9 for all Starfleet personnel. (DS9: "Call to Arms")
Sciences officer 2 []

A female officer
This female sciences officer worked on the bridge of the Defiant during the final attack against the Dominion in the Dominion War. She manned an aft station when her console exploded and she fell over another console. Later, she was working on an aft station of the bridge. (DS9: "What You Leave Behind")
Sciences officer 3 []

At Quark's bar
This male sciences officer visited Quark's bar and was seated near the dabo table where he had a drink when Garak entered the bar and talked to Quark about the future. (DS9: "The Way of the Warrior")
He walked along the Promenade when Lenara Kahn and her brother Bejal Otner talked about her feelings for Jadzia Dax. (DS9: "Rejoined")
He passed Quark's bar on the Promenade when Dax interrupted Bashir's conversation with Morn to play a game of darts with him. (DS9: "Starship Down")
Vulcan officer []

A Vulcan sciences officer
This Vulcan sciences officer served aboard Deep Space 9 in 2372.
During the strike of the employees of Quark's, O'Brien saw her and told Julian Bashir that she'd not patronize Quark's during the strike, predicting that the ethics her species were known for would make her supportive of the Guild of Restaurant and Casino Employees. He was right, she passed the establishment. (DS9: "Bar Association")