Summary: End-stage renal failure and clinical evidence of renal disease are more frequent in Australian Aboriginals than in the non-Aboriginal Australian population. to investigate the lesions responsible for this excess a systematic study of renal biopsy findings in a series of Aboriginal patients in South Australia and the Northern Territory was performed and the data on these patients were compared with a consecutive series of renal biopsy findings in non-Aboriginal patients. Histological and morphometric comparison was made between biopsies from 206 Aboriginal and 690 non-Aboriginal patients. the distribution of glomerular lesions was found to differ significantly between the Aboriginal and non-Aboriginal groups: diabetic glomerulosclerosis, idiopathic glomerular enlargement (glomerulomegaly), mesangiocapillary glomeru-lonephritis (MCGN), and non-IgA mesangiopathic glomerulonephritis (GN) were found more frequently in the Aboriginal population, whereas there were fewer than expected examples of thin membrane nephropathy, minimal change disease and membranous GN. Diabetic glomerulosclerosis was significantly more frequent, and the lesions more severe, in Central Australia (where diabetes is more prevalent) and glomerulomegaly was especially common in Bathurst Island. These two conditions accounted for one third of the series and evidence is presented to suggest that a substantial proportion of renal disease in Aboriginals may be the consequence of conversion to a Western life style. of the 206 Aboriginal patients, 23 presented with chronic renal failure, suggesting either late presentation or unusually aggressive renal lesions, and 10 had end-stage renal disease on biopsy.