The competition will be open to 6-15 year-olds who can enter by drawing their design, giving their mascot a name and writing about how they came up with their idea.
The winner will get the opportunity to walk out on the pitch at Wembley Stadium with their mascot at The FA Cup Final on Saturday 30 May.
They will also get a behind-the-scenes tour of the stadium and the BBC Sport studio and be able to stay and watch the match too.
The entries in second and third place will get to attend an FA Cup Semi-Final and go behind-the-scenes of Wembley. 30 runners-up will also earn their Blue Peter Orange competition badge.
To inspire the viewers, Radzi Chinyanganya and his fellow Blue Peter presenters were joined by a selection of different mascots from clubs around the UK, including: Farnworth (from MOTD Kickabout), Fred the Red (Manchester United, Gunnersaurus (Arsenal), Cyril the Swan (Swansea), Filbert Fox (Leicester), Jaggy MacB (Partick Thistle) and Jude the Cat (QPR).
Leading the judging panel for the competition will be BBC Football pundit Robbie Savage who says: "I love a good mascot and I am sure that Blue Peter viewers will be able to design one of the best! Radzi reckons that he will be the one wearing it on the day but he might have to fight me for it."
The competition will launch on Blue Peter on Thursday 12 February, CBBC, at 5.30pm and closes at 12 noon on Friday 20 March.
All the terms and conditions, as well as the entry form, are on the Blue Peter website here.
