Articular cartilage degeneration was studied in an experimental model including 68 knees of adult dogs on which five different types of medial meniscectomy had been performed with a followup period of 10 to 450 days. The results were assessed by macroscopic, radiologic, and histologic methods. The degenerative lesions increased proportionally to the amount of meniscal tissue resected and the duration of observation. These lesions proved to be more intense at the tibial plateau compared to the femoral condyle. For both joint surfaces the predominant location was the central zone. Considering the degenerative process by the articular cartilage after total meniscectomy, maximum preservation of meniscal tissue is recommended.