A total of 391 strains of salmonella isolated from patients with sporadic cases of diarrhea during the period from April 1985 to June 1989 in Yamanashi Prefecture, were tested for their serovars, drug susceptibility and conjugative transmissible R plasmids. The results can be summarized as follows: 1) The isolates were serologically classified into 35 different serovars. The predominant serovars were S. Typhimurium (24.8%), S. Litchfield (9.2%), S. Oranienburg (9.0%), S. Enteritidis (7.9%) and S. Hadar (6.1%). 2) Serovars of S. Hadar, S. Brandenburg, S. Chester, S. Chailey, S. Oslo and S. Inchpark were isolated from human sources for the first time in Yamanashi Prefecture. 3) Monthly frequency of isolates were August (17.3 strains), September (11.3 strains) and May (10.6 strains). 4) The predominant ages of isolates were 2 years of age (17.1%), 1 years of age (15.1%), 3 years of age (11.2%), under 1 years of age (10.7%) and 4 years of age (9.8%). 5) The rate of isolates from male were higher than female. (Male: 57.5%, Female: 42.5%). 6) The frequency of resistant isolates was 45.8% in the period. The most predominant resistance pattern was SA.SM.TC.CP.KM.ABPC resistance (11.2%). Conjugative transmissible R plasmids appeared in 41.3% of the resistant strains. 7) The number of resistant strains of S. Typhimurium was 57 out of 97 strains (58.8%).