Streptococcus(Str.) uberis known as the causative agent of environmental mastitis was isolated from the raw milk and environmental specimens of the 9 dairy farms located in Kyunggido Korea. Genotypings by pulsed field gel electrophoresis(PFGE) analysis of Sma I digested genomes have been conducted in order to elucidate the contamination route into raw milk, and determined their susceptibility to 19 antibiotics. Str. uberis could be isolated in 11.4% of total samples tested, 19 isolates of Str. uberis could be typed into 7 genotypes by PFGE. Str. uberis found in milk samples originated from the environmental sites and animal body. High degree of heterogeneity in genotype and in antibiotic resistance was revealed and even the strains which had identical genotypes showed different chloramphenicol and vancomycin resistance. Each genotype of Str. uberis revealed a typical pattern of antibiotic susceptibilities.