A young man employed at the local aquarium was bitten by a bottlenose dolphin (Tursiops truncatus) during a training session, receiving a slight injury which healed rapidly. Some two months later fluctuant swellings appeared in the region of the bite, which developed into indolent ulcers which have not completely healed seven months after the original bite. Cultures taken on two occasions have yielded a pure growth of Mycobacterium marinum.