Results of a comprehensive dental examination, including a histologic evaluation, of a patient showing unilateral odontodysplasia revealed no hint as to the origin of the abnormality. A complete medical examination also resulted in negative findings, with the excetion of congenital bilateral talipes equinovarus. The genetic history was negative, and results of chromosomal studies of the child and her mother revealed no abnormalities. Neither had an anatomic or a functional abnormality, with the exception of the odontodysplasia in the child. Results of laboratory studies including complete blood counts, urinalyses, ferric chloride tests of the urine, and electrolyte tests also were negative. The special considerations given in this case in an attempt to establish a possible causation of the abnormality were inconclusive. We think, however, that the management of the patient was successful in regard to the prosthetic appliance, and every attempt will be made to follow up the patient to ensure a good prognosis of the remaining developing dentition.