The case presented is that of a 23-year-old man suffering from osteochonditis dissecans (OCD) of the medial femoral condyle, in whom a free piece of cartilage had separated off and there was a large osteochondral defect despite numerous operations. After refixation of the fragment failed, an autologous chondrocyte transplantation (ACT) was performed using the sandwich technique. Three years after the operation the patient is very satisfied with the result. The radiological findings show stable repair of the bony and cartilaginous defect area. This case report shows that ACT is a valid method for the treatment of large osteochondral defects even after several previous failed operations. The low donor site morbidity is an important advantage over other methods, such as transplantation of osteochondral plugs.