The authors present two case histories of children with synovial soft tissue tumor of the ankle. Synovial soft tissue tumors of the ankle in childhood are rare. The symptoms are unspecific so that the clinical diagnosis is difficult. In both cases the children came primarily to the clinic with painful swelling at the ankle after trauma, which further complicated the diagnosis. It should be taken into consideration that the rare differential diagnosis of pain at the ankle could be synovial soft tissue tumor especially when the clinical course is protracted.