Distribution of Salmonella organisms has geographical characteristic.In order to study the etiological organism and the route of transmission with case when an outbreak or epidemic/epizootic of salmonellosis occurs in a certain area, surveys on Salmonella distribution have been conducted by many scholars overseas by using the KAUFFMANN WHITE classification table of Salmonella. Recently, in Japan, the Committee on Enteric Bacteria of Animals has disclosed the presence of more than 55 types of bacteria, including Salmonella enteritidis, as the result of its nation-wide survey. The committee has drawn conclusions from this survey that, as the state of Salmonella distribution in Japan is represented by that among stray dogs in large cities, especially in Tokyo and Osaka, a study on Salmonella organisms harbored by stray dogs in these cities will make it possible not only to presume the state. of Salmonella distribution all over the country but also to predict the type of Salmonella to be epidemic/enzootic in the future. The present detection survey was conducted to elucidate the state of Salmonella distribution among stray dogs in Tokyo Prefecture in 1957, based on the conclusions issued by the above-mentioned committee. The materials used were 200 dogs destroyed at the Central Dog Pound at Mikawashima, Tokyo. Mesenteric lymph nodes were collected aseptically from them. Bacterial detection was performed on these lymph nodes within 1 to 2 hours after they were harvested, both concentration and direct cultivation techniques being employed. The results obtained are as follows.1. From mesenteric lymph nodes of 200 stray dogs, 29 strains (14.5 per cent) of Salmonella were detected.2. These strains were Classified into 8 types; namely, 7 strains of S. enteritidis, 6 of S. stanley, 4 of S. typhimurium, 4 of S. narashino, 3 of S. tananarive, 3 of S. give, one of S. thompson, and one of S. bredeney.3. Among the results of the present survey, the increasing rate of S. stanley and the appearance of S. tananarive attracted attention. Above all, it is for the first time in Japan that S. tananarive was detected.