第 4 季 共 20 集
播出时间：2007年9月28日
第 1 集 Adrift (2)
播出时间：2007年9月28日
Floating in deep space with the city's protective shield failing, the team must do all they can to keep Atlantis alive. A radical injury threatens Dr. Weir's life.
第 2 集 Lifeline (3)
播出时间：2007年10月5日
Colonel Sheppard and his team embark on a risky mission to steal a Z.P.M. power module from the Replicators -- but must rely on a compromised Dr. Weir to succeed.
第 3 集 Reunion
播出时间：2007年10月12日
When a group of Ronon's people enlist the team's help in raiding a Wraith weapons facility, Ronon reconsiders whether his future lies in Atlantis or with his friends.
第 4 集 Doppelganger
播出时间：2007年10月19日
During an off-world mission Colonel Sheppard unknowingly becomes host to an alien entity, which infects others in Atlantis and afflicts them with terrifying nightmares.
第 5 集 Travelers
播出时间：2007年10月26日
Colonel Sheppard is captured by the inhabitants of a generational ship and their beautiful leader, who wish to use his ability to use Ancient technology for their own ends.
第 6 集 Tabula Rasa
播出时间：2007年11月2日
When a virus causes amnesia in everyone except Teyla and Ronon, the Atlantis team must work together to find a cure before their memories fade entirely.
第 7 集 Missing
播出时间：2007年11月9日
During a visit to New Athos, Teyla and Dr. Keller find themselves on the run from a primitive tribe of warriors.
第 8 集 The Seer
播出时间：2007年11月16日
The team meets a man with extraordinary prophetic abilities, who gives them a dark prediction about Atlantis's future. The Wraith seek a new alliance with Atlantis in their war with the Replicators.
第 9 集 Miller's Crossing
播出时间：2007年11月30日
Rodney McKay goes in search of his sister on Earth after she is kidnapped by the head of a powerful corporation.
第 10 集 This Mortal Coil (1)
播出时间：2007年12月7日
A mysterious drone crashes into Atlantis, indicating that the Replicators may have found the city. But when Elizabeth Weir appears, the team realizes that the probe is just a part of a bigger mystery.
第 11 集 Be All My Sins Remember'd (2)
播出时间：2008年1月4日
With a plan to potentially extinguish the Replicator threat, the Atlantis team must seek an alliance with a fleet of Wraith ships.
第 12 集 Spoils of War
播出时间：2008年1月11日
The team finds their former Wraith ally's hive ship drifting in space, which leads them to a secret project that could turn the tide of a civil war.
第 13 集 Quarantine
播出时间：2008年1月18日
An automated lockdown traps Atlantis personnel in various parts of the city, each of them hoping the others will come to their rescue.
第 14 集 Harmony
播出时间：2008年1月25日
Colonel Sheppard and Dr. McKay must protect a child princess on a pilgrimage before she can become queen, and learn that she has dangerous enemies threatening her life.
第 15 集 Outcast
播出时间：2008年2月1日
While on personal leave on Earth, Sheppard and Ronon learn that scientists have engineered a human-form Replicator -- who is now on the loose.
第 16 集 Trio
播出时间：2008年2月8日
McKay, Carter, and Keller are trapped in an underground chamber while on an off-world mission, with no apparent means of escape.
第 17 集 Midway
播出时间：2008年2月15日
Teal'c visits Atlantis to counsel a headstrong Ronon, who is up for review by the I.O.A. But the two must work together when the Wraith invade the Midway space station in order to reach Earth.
第 18 集 The Kindred (1)
播出时间：2008年2月22日
As a mysterious new illness sweeps through the Pegasus Galaxy, Teyla is convinced by a vision that the father of her child is trying to communicate with her.
第 19 集 The Kindred (2)
播出时间：2008年2月29日
The team is shocked when an old friend, believed to be dead, miraculously returns to them. Teyla plans an escape from Michael's captivity.
第 20 集 The Last Man (1)
播出时间：2008年3月7日
Sheppard returns to Atlantis after a mission and finds the city abandoned, all systems dead -- and instead of ocean, sand dunes as far as the eye can see.
