Four hundred and ninety-three patients were admitted to the Royal Darwin Hospital in 1980 with urinary tract disease. Aboriginals had an increased incidence (p less than 0.005) of urinary tract infection and glomerulonephritis (p less than 0.001) compared with non Aboriginals. Aboriginals with post-streptococcal glomerulonephritis tended to grow Group A Beta hemolytic streptococci from their skins, non Aboriginals tended to grow it from their throats. Aboriginals had a lower incidence of urolithiasis (p less than 0.001). There was no difference in the incidence of benign prostatic hypertrophy between the two populations.