Tissues from healthy subadult and moribund newborn northern fur seals (Callorhinus ursinus) on St. Paul Island, Pribilof Islands, Alaska, and from healthy pups and yearlings on San Miguel Island, California, were sampled for bacteria and fungi. Corynebacterium spp. and Staphylococcus spp. were more frequently present in tissues from animals on St. Paul Island whereas Pseudomonas spp. were frequently isolated on San Miguel Island. Approximately half of the blood samples were positive for bacteria. Salmonella spp. were isolated from rectal swabs of animals only on San Miguel Island. Fungi were isolated from the hair and skin of subadult males.