Four patients with histologically confirmed osteonecrosis of the first metatarsal sesamoid are presented. No patient was an athlete, nor recalled any noticeable trauma or significant stress as having occurred to the feet. No foot deformities or joint malalignments were found. Excellent results were obtained by excision of the affected sesamoid in all patients, after follow-up periods of 1 to 12 years. Microscopic findings were compatible with those seen in idiopathic osteonecrosis of the femoral head.