A total of 94,827 Escherichia coli strains isolated from cattle, sheep, pigs and poultry during the years 1971 to 1977 were tested for resistance to six antibiotics using a disc diffusion technique. The percentage of strains resistant to chloramphenicol (10 microgram), streptomycin (10 microgram), tetracycline (10 microgram), neomycin (10 Microgram) and furazolidone (15) were 16.8, 53.9, 42.7, 18 and 10.9 per cent, respectively; 52.2 per cent of strains (1971 and 1972) were resistant to 2 microgram ampicillin and 27.8 per cent of strains (1973 and 1977) were resistant to 10 microgram ampicillin. There was no evidence of an overall increase in antibiotic resistance during the seven year period. The animal species of origin was recorded for each of the 55,494 E coli strains examined during 1974 to 1977; 31,763 strains were isolated from cattle, 15,688 from pigs, 4582 from sheep and 3191 from poultry. Considerable variations in antibiotic resistance were recorded for strains isolated from different species.