Osteochondritis dissecans (OCD) is thought to be an acquired osteochondral disorder, and its etiology may be multi-factorial. Trauma, both acute and repetitive events, has previously been proposed as a potential cause for OCD development. We present two cases of skeletally immature males who developed a symptomatic OCD lesion following a femoral condyle bone contusion. These cases suggest that an acute traumatic event may lead to the development of OCD of the knee.