One hundred adult Sudanese patients who presented to Soba University Hospital (SUH) with established chronic renal failure (CRF) were studied to determine the aetiology. Thirty-eight had chronic glomerulonephritis, 12 renal calculi, nine diabetic renal disease, seven chronic pyelonephritis, five sequelae of acute renal failure (ARF), four renal vascular disease, three polycystic disease of the kidneys, and two obstructive uropathy. In 20 patients the aetiology was not determined because of late presentation to hospital. The results were compared with those of the developed countries, which differ greatly from Sudan in climate, diet, race, culture and social habits. The main differences were in the prevalence of renal calculi which, although being the second commonest cause of CRF in the Sudan, were rare in European countries. Also, diabetes mellitus was a much commoner cause of CRF in Sudan than Europe. Other aetiological factors were similar.