During implantation of radiotelemetry devices in sea otters (Enhydra lutris) at the Seward Otter Rehabilitation Center, surgical team members noted ulcers in the oral cavity of each of five animals examined. Oral lesions were identified in 25 of 27 otters examined at the center. Histological evaluation of the lesions revealed focal areas of mucosal epithelial necrosis with associated intranuclear viral inclusion bodies. A herpes-like virus was subsequently identified ultrastructurally. The concern of releasing a virus of unknown origin and virulence into a naive wild otter population prompted management decisions restricting the movement of otters and jeopardizing the scheduled release of the otters on 27 July 1989. A team of veterinarians and otter capture personnel captured and examined 12 free-living adult otters off the coast of the southern Kenai Peninsula. Viral-induced oral lesions were identified in many of these animals establishing that the virus was indigenous to sea otters living in Alaskan waters; rehabilitated otters were released back into the wild.