His team - Mike's Gym, headed by Mike Passandier - made the announcement earlier this evening, according to German-language site Ground and Pound.de
Manhoef apparently wants to spend more time with his young family, which has been difficult recently.
"Training seven days a week and three times a day has taken its toll on his family life" a spokesman explained.
No comment has yet been made as to how permanent the retirement is likely to be, or whether it applies to his MMA activity rather than his K-1 kickboxing career.
