The Ice Warriors were another monster introduced in Season 5, hot on the heels of the popular Yeti. These reptiles from Mars became arguably the show's third most popular monster, behind the Daleks and the Cybermen.

The Doctor, Victoria and Jamie emerge from the Tardis into a frozen landscape. Having just left Det-sen monastery, they first think they are still in the Himalayas. They have, however, travelled far into the future. It is the year 3000, and Earth is threatened by the onset of another ice age. Nearby is Britainnicus Ice Base, where the slightly unstable Leader Clent and his team of scientists are using an ionizer to halt the relentless march of the glaciers. Earth society has somewhat rashly placed its faith in technology in general and computers specifically, a common Sixties SF theme. Clent and his team are no exception. The Doctor of course knows better.

Meanwhile, out on the ice, a survey team has found something big, green and humanoid frozen in the glacier. They cut it from the ice and return with it. Left alone in the lab, Victoria doesn't notice the ice melting and the creature within it slowly moving.

The Ice Warriors was written by Brian Hayles, who had previously contributed two stories in previous seasons, The Celestial Toymaker and The Smugglers. He was inspired by the discovery of a mammoth found frozen in Siberian ice, but unlike the Ice Warrior in the base, the mammoth didn't come back to life when thawed out. Hayles would go on to write three further stories for his reptillian creations, The Seeds of Death in Season 6, and the two "Peladon" stories of the Pertwee era.

As with the Cybermen, tall actors were cast as Ice Warriors. In their debut story the leader of the Ice Warriors, Varga, was played by Bernard Bresslaw. Bresslaw is perhaps better known for his various roles in many of the "Carry On...." series of films. Another Ice Warrior was Sonny Caldinez, who previously played Kemel the Turk in The Evil of the Daleks. Caldinez would go on to become a regular Ice Warrior in all of their subsequent stories.

Episodes 2 and 3 are missing. In 1983 Episodes 1, 4, 5 and 6 were found by chance in a cupboard in Villiers House, the former home of BBC Enterprises. The BBC release of The Ice Warriors contains these remaining episodes, with a 15 minute reconstructed link in place of the two missing episodes. The Ice Warriors package also contains an audio CD of episodes 2 and 3, and The Missing Years documentary, hosted by Frazer Hines and Deborah Watling.

The Missing Years contains several of the Australian Censor Clips (notably from The Macra Terror and Fury from the Deep), the Galaxy 4 episode 1 extract, and The Underwater Menace episode 3 in its entirety.