We report two cases of nontraumatic metatarsal pain with sclerosis and fragmentation of the lateral sesamoid bone on roentgenographs and computed tomography images. One patient underwent magnetic resonance imaging (MRI), which showed low signal from the sesamoid bone. These imaging findings suggested osteonecrosis. Histology of the sesamoidectomy specimen confirmed this diagnosis in one patient. Avascular necrosis of the metatarsal sesamoid is an uncommon disorder. The suggestive roentgenographic and MRI findings rule out the other painful conditions of the sesamoid bone. The features are reviewed and the treatment options discussed.