Clinical, biochemical, radiological and bone biopsy findings were studied in 15 patients with end stage renal disease due to analgesic nephropathy and compared with data from age and sex matched controls who had end stage renal disease from other causes. Patients with analgesic nephropathy had significantly higher osteoid volume (P < 0.04), reduced calcification fronts (P < 0.001) and lower percentage mineralization (P < 0.04). Serum alkaline phosphatase was significantly higher in the analgesic group (P < 0.005). It is concluded that osteomalacia is more common and severe in the group of patients with end stage renal disease due to analgesic nephropathy. There was no relationship between osteomalacia and the duration of renal failure, acidosis, aluminium deposition or other serum biochemical abnormalities.