The authors present three cases of epiphyseal chondroblastoma localised adjacent to the femoral intercondylar fossa which proved to be relatively common in a recent review of the case material of the G. Pini Institute of Milan (3 out of 22 cases). They were able to deduce various features of value in diagnosis and treatment which enable a single stage operation to be planned. This consisted of curettage with or without spongy bone transplants, and can be carried out even when the articular cartilage has been breached. The long term results in all three cases were satisfactory.