We studied the clinical characteristics and the epidemiology of primary septicemia associated with Vibrio vulnificus in 70 patients. All patients came from the western and southern coastal areas of Korea. Most cases (96%) occurred during the summer months, in men (96%), and in persons 40 or more years of age (90%). The illness of 46 patients (66%) began with septicemia, often within 2 days of the consumption of raw seafood. Forty-seven patients (67%) had preexisting hepatic disease, and 49 (70%) had a history of alcoholism. Of the 70 patients, 45 (79%) died. The cutaneous lesions that were present on admission in 64 patients (91%) appeared on the legs in 51 of the cases. V. vulnificus was isolated from the blood of 65 patients tested and from the skin lesions of 51 of 55 patients tested. The histopathologic findings differed according to the clinical stage of lesions. Because V. vulnificus septicemia is a highly fatal disease, persons with liver disease or alcoholism should avoid eating or handling raw seafood.