We studied the degenerative changes of acetabulum, examining the acetabular articular cartilage at weight bearing dome area from the hips of 25 avascular necrosis of femoral head cases. Histological- histochemical studies demonstrated 4 mild, 19 moderate and 2 severe grade of degenerative arthritic change. This has confirm that even in early stage of avascular necrosis of femoral head, there are degenerative arthritis in acetabular cartilage. This may influence the prognosis of bipolar hemiarthro- plasty in avascular necrosis of femoral head patient.