The Channel 4 afternoon show - which has now been running since the station launched in 1982 - reaches its 6,000th edition today and is now into its 70th series.
Viewers will see an official from Guinness World Records hand over an award to presenter Nick Hewer, co-hosts Rachel Riley and Susie Dent in recognition of the programme's achievement, attaining "most series broadcast for a TV game show".
Hewer said: "It is a huge honour to front Countdown, now recognised by Guinness World Records for its longevity.
"Having 32 years under its belt, I am only a novice, coming up to three years on the show. But I and the whole team are incredibly proud to be part of such a durable and intelligent format that relies on intellect rather than prize money."
Craig Glenday, editor-in-chief at Guinness World Records, said: "The show - the first ever shown on Channel 4 - has long been a cornerstone of British popular culture, and its 70 series attest to its class, quality and pure entertainment value.
"It's every bit a part of TV time as the cuppa itself, and I'm looking forward to its next 6,000 episodes."
The show was launched by late presenter Richard Whiteley and launched the career of media personality Carol Vorderman.