Among radiolucent lesions of the carpal bones, intraosseous ganglions are the most frequent. Most cases involve the lunate or scaphoid bones in the wrist. Two twin sisters aged 23 years were examined for the complaint of left-sided wrist pain. Physical examination and radiologic findings showed unilateral and symmetrical lesions in the left scaphoid bone suggesting intraosseous ganglions. Both patients underwent ganglion excision and grafting using autografts taken from the ipsilateral distal radius. Both patients were free of wrist pain during a three-year follow-up. Histopathologic examination of the excised lesions was consistent with intraosseous ganglion. Unilateral and symmetrical involvement of the same bone in these twin sisters suggests genetic transmission, which has not been previously reported for intraosseous ganglions.