In the course of nationwide investigation on epidemiological characteristics in Salmonella Typhimurium isolates from food-producing animals in Japan between 1999 and 2001, fifty-seven isolates of S. Typhimurium DT104 and 104B obtained from cattle and swine at farm level in Japan between 1999 and 2001 were classified with pulsotype and antimicrobial resistance type. Most of the isolates were resistant to five or more antimicrobials and were genotyped into four groups. The present nationwide investigation shows that at least 11 types of S. Typhimurium related to DT104 are prevalent among food-producing animals across the country.