A 17-year old male bottlenose dolphin (Tursiops truncatus) housed in an open sea pen for 11 years was under observation for chronic low weight, anemia, and a recent episode of severe colic. This dolphin expired suddenly during a physical examination. A postmortem was conducted at the site within two hours. Cause of death was not apparent based on gross examination of organs and subsequent tissue histopathology. Ulcerations with petechial hemorrhages in the first stomach compartment were noted. Internal organs were carefully exposed and tissues cultured for bacteria on blood agar, TCBS, and marine agar. Vibrio vulnificus was the predominating bacterium recovered in the three media from blood, spleen, heart, kidney and stomach. In comparison, no bacteria were recovered from internal organs of another bottlenose dolphin which had expired under similar conditions from blastomycosis. Based on these results and the known virulence of V. vulnificus, we conclude that septicemia resulting from V. vulnificus infection of this dolphin, perhaps gaining entrance through the gastric ulcers in the stomach, was instrumental in causing the animal's death.