Of 233, 427 swine inspected in the Sapporo Muni. cipal Abattoir, Hokkaido, over a period from April, 1963, to January, 1970, 154 animals (0.065%) were found infected with swine erysipelas. Of them, 114 belonged to the urticaria form and 40 to the endocarditis form. The frequency of occurrence was high in summer and low in winter. The increasing prevalence of the endocarditis form was outstanding. This form was found in 4.2 and 51.7% of the entire erysipelatous swine in 1964 and 1969, respectively. In the 40 cases of this form, lesions were mostly observed at the left atrioventricular value, and the etiologic organism was isolated from the principal organs all over the body. Ten cases were selected from among the forty and subjected to a trial to detect causative bacteria from muscle with positive results. The fluorescent antibody technique was applied successfully to the detection of swine erysipelas. It was more sensitive than the cultivation method and available for a rapid and accurate means for diagnosis of this disease. Ten strains isolated were subjected to typing. Of them, 2 and 3 strains derived from the urticaria and endocarditis form, respectively, were classified into the B type and 5 strains from the endocarditis form into the A type.