Incidences of various infectious diseases in 986 autopsy cases at Hiroshima Atomic Bomb Hospital and Hiroshima Red Cross Hospital from 1965 to 1975 were compared according to the distance from the explosion place, and the following results were obtained. There was not a significant difference at incidences of most infectious diseases between each exposured group and not-exposured group. Incidence of old tuberculosis focus was a little higher in exposured groups, but incidences of main lesions such as tuberculosis, active tuberculosis, and miliary tuberculosis were lower in exposured groups and effect of exposure was negative. Out of urinary tract infections, the nearer the distance to the explosion place was, the higher incidence of cistitis in female was. Incidence of cystitis of female was higher than that of male in the group exposured near to the explosion place. With respect to stomach cancer, leukemia, malignant lymphoma, and cerebrovascular disorder, the nearer the distance to the explosion place was, the higher incidences of various infectious diseases were.