Fourteen children affected by juvenile osteochondritis dissecans of the medial femoral condyle (16 knees) were treated by arthroscopic drilling of the lesion. The average age at operation was 12.8 years, and all the knees had open physes. Conservative treatment including restriction of activities had been unsuccessfully attempted in all cases for a period of > 1 year on average. At surgery each lesion was shown to have intact articular cartilage. All the lesions progressed to healing, and the patients were asymptomatic at an average of 56 months after the operation. Radiographic examination showed reconstitution of a normal or minimally flattened profile of the medial condyle. Arthroscopic drilling of the lesion in knees with juvenile osteochondritis dissecans and intact articular cartilage was effective to promote healing. The low morbidity and easy rehabilitation justify the procedure for these young patients when conservative measures fail.