Osteochondritis dissecans (OCD) is a disorder in which a fragment of cartilage and subchondral bone separate from an articular surface. Within the knee, OCD lesions occur most often on the medial femoral condyle. The etiology of OCD remains uncertain. Approximately 40% of patients have a history of major or repetitive knee trauma and 60% of patients participate in a high level of athletic activity. The treatment of juvenile OCD is determined by the stability, location, and size of the lesion. We report two cases of OCD of the medial femoral condyle. The first is an 18-year-old girl with bilateral OCD in whom the lesions successfully healed following conservative treatment. The second case is a 12-year-old girl treated with transarticular drilling and screw fixation. We present our clinical results and discuss treatment rationale.