Toxic editor Matt Yeo is leaving the fortnightly magazine to start his own publishing company.
Yeo leaves on 16 January. His new company, SkyJack Publishing Limited, will be doing contract publishing for a number of media companies.
Andy Davidson will take on the role of acting editor until a replacement is found.
Toxic is a lifestyle magazine for 7 to 12 year-old boys. It covers features, competitions, pull-out posters, reviews, gags, sports, video games, movies, TV, music, fashion and toys.
Toxic is published by Egmont Magazines.