Subchondral phalangeal bone cysts frequently are encountered when reviewing foot x-rays. Radiologically, these lesions appear as a focus of subchondral radiolucency surrounded by a rim of sclerotic bone. Radiologic and histologic examinations demonstrate that these lesions are identical to the subchondral bone cysts associated with osteoarthritis of the hip and the more recently described cysts of the hallucal sesamoids and the head of the first metatarsal.