Vibrio vulnificus causes very severe infections. The organism is isolated, for the most part, from the blood, and skin lesions. Isolation from other sources, including the urine, is very rate. Four cases of V. vulnificus septicemia were bacteriologically diagnosed in 1984 and 1985 at Severance Hospital. All of the patients were men, 42 years and older, with preexisting liver disease. All of them showed hypotension and secondary skin lesions, and all expired. The organism was isolated from the blood in all patients, from the peritoneal fluid in one, and from skin lesions in two. From one patient, isolation from a urine speAmen was also accomplished. All of the isolates were typical in their characteristics such as in their forming green colonies on Thiosulfate citrate bile sucrose (TCBS) agar, delayed acid production from lactose, and growth in broth with 6% NaCl.