A 15-year-old boy of Turkish origin presented with a painful swollen left knee. An X-ray revealed osteochondritis dissecans of the lateral femoral condyle. Arthrotomy was performed and the fragment was fixated with tissue glue and 2 absorbable pins. Eight months later, a large recurrent osteochondral fragment of the lateral femoral condyle was seen on X-ray. The patient was re-operated, during which operation the fragment was found and fixated with three compression screws. One year after the first operation the patient developed similar complaints in the contralateral knee; this knee also contained osteochondral fragments necessitating surgery. Osteochondritis dissecans of the knee is a multifactorial disease in which part of the cartilage of the femoral condyle becomes unattached from the subchondral stratum, usually on the lateral side of the medial femoral condyle. Initially, an inflammatory reaction was thought to be the cause of osteochondritis dissecans. Because of the lack of white blood cells, a previous trauma is a better explanation for the ultimate loosening of the cartilage. The treatments that are described for osteochondritis dissecans are conservative treatment, operative fixation, with or without subsequent chondrocyte transplantation or osteochondral autograft transplantation, and finally microfracturing.