A patient is reported who had a partial terminal deletion of the long arm of chromosome No. 6. His clinical findings included development delay, failure to thrive, neurologic abnormalities, and multiple congenital malformations. Among the malformation were unusual facial features, cleft palate, atrial septal defect, and abnormalities of the external genitalia. The patient's features are compared with others who may have material deleted from the long arm of chromosome No. 6.