In the year 3000, the Earth is on the brink of a new Ice Age, as the countries of the world are buried beneath mammoth glaciers. The Doctor, Jamie and Victoria arrive in England as a small team of scientists desperately tries to hold back the ice. But a new threat comes when an ancient spaceship is discovered frozen in the glacier. Soon its crew, the warlike Ice Warriors from Mars, reawaken and become intent on delivering themselves from the planet, at any cost.

It had been about a year since Brian Hayles had written The Smugglers, the penultimate adventure of the First Doctor, when he was asked once again to contribute to Doctor Who. During the spring of 1967, producer Innes Lloyd and story editor Peter Bryant discussed the introduction of a new regular monster race, alongside the Daleks (whose future use would be limited due to the efforts of their creator, Terry Nation, to sell a series featuring them to Hollywood) and the increasingly-popular Cybermen. They turned to Hayles to develop such a creature.

Hayles found inspiration in an article he had recently read about a prehistoric mammoth, whose well-preserved corpse had been discovered buried in the Siberian ice in August 1900. He was also intrigued by the planet Mars, and wanted to develop a race which could conceivably have flourished in such an environment. With these ideas as his starting point, Hayles was commissioned to write The Ice Warriors on July 21st. For some time in mid-summer, it was unclear whether this story or The Abominable Snowmen would be the first into production as part of Doctor Who's fifth recording block. In the event, The Ice Warriors was held back, and it was designated as Serial OO. During the summer months, Victor Pemberton also worked on Hayles' scripts, having been promoted to story editor while Peter Bryant was given a test run in the producer's chair. Subsequently, when Bryant returned to his usual job, Pemberton decided to leave Doctor Who altogether.

Hayles envisioned the eponymous Ice Warriors as Viking-like cybernetic creatures, with high-tech instruments on their armour and helmets. Costume designer Martin Baugh, however, saw the creatures as more reptilian, with the armour and helmet actually appearing as part of the monsters' carapace. This met with the approval of Derek Martinus, the story's director. Martinus had most recently handled The Evil Of The Daleks toward the end of the previous production block.

Filming began on The Ice Warriors at the Ealing Television Film Studios on September 25th, and covered five consecutive days. This largely involved scenes set in the glacier and in the wilderness outside Brittanicus Base. On the 27th, Patrick Troughton received a new contract, which covered The Ice Warriors and three further six-part serials. Deborah Watling also received a contract extension, securing her services for both the present story and The Enemy Of The World, which would be the next to go before the cameras.

Studio recording took place, as usual, at Lime Grove Studio D on consecutive Saturdays beginning on October 21st. In the interim, Martinus had asked that a new helmet be constructed for Bernard Bresslaw, who played the main Ice Warrior, Varga. The original helmets were very bulky and restrictive, so a slimmer, more flexible version was devised. Unfortunately, this meant that Varga's appearance would shift noticeably between the prefilmed segments and those recorded in the studio. The revised costume made its debut for the taping of episode two on October 28th. (The other Ice Warrior costumes would also undergo varying degrees of refurbishment over the course of the next week.) The same day, a special trailer was recorded for The Ice Warriors, featuring Peter Barkworth and Peter Sallis in-character as Clent and Penley, respectively. This was broadcast at the end of The Abominable Snowmen part six on November 4th.

The final installment of The Ice Warriors was taped on November 25th. Unfortunately, Watling was not available for that evening. Consequently, all the scenes for which her character was essential were recorded in the afternoon. For the evening, the scripts were rewritten to have the Doctor send Victoria (unseen) back to the TARDIS; she was originally supposed to return to Brittanicus Base with him and appear in the final control room sequence. Jamie took on one of Victoria's lines as a result.

• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing, ISBN 0 426 20516 2.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing, ISBN 1 85227 420 4.
• Doctor Who Magazine #303, 2nd May 2001, “Archive: The Ice Warriors” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Heroes And Villains” by Andrew Pixley, Panini Publishing Ltd.