A vervet monkey (Cercopithecus aethiops) housed at quarantine of Razi vaccine and serum research institute died following a few days of sickness. Multiple abscesses on the surface and inside the liver and enlargement of spleen with pinpoint white spot were the most prominent macroscopic features. We examined the organs of the dead monkey and Yersinia enterocolitica was isolated. In histopathologic examination of the liver, spleen and intestine sections, acute hepatitis, splenitis and enteritis were evident. This is the first report of fatal case of Y. enterocolitica infection in vervet monkey from Iran .