A captive, 18-year-old male Nicobar pigeon (Caloenas nicobarica) with a history of intermittent lameness associated with osteoarthritis in the left tarsometatarsal joint was found dead in its enclosure and submitted for postmortem examination. On gross examination, the left adrenal gland was enlarged and histologically was confirmed as a pheochromocytoma (chromaffin cell tumor). When functionally active, pheochromocytomas can cause nonspecific clinical signs associated with the cardiovascular, nervous, urinary, respiratory, and digestive systems. The majority of clinical signs in animals with this tumor are vague and nonspecific, making antemortem diagnosis challenging. Pheochromocytomas are rare tumors in humans (occurring in 0.20–0.04% of all tumors) and even rarer in animals. Only 2 other cases of this tumor in avian species, a budgerigar (Melopsittacus undulatus) and a 14-week-old chicken (suspected case), have been reported.