A case is presented of fetal teratogenic damage from an unusually high maternal dosage of diphenylhydantoin, 600 mg daily, to a 40-kg woman throughout pregnancy. The anomalies included narrowed ends of the fingers and toes; aplasia of the nails on the other fingers and toes; aplasia of the distal phalanges of the fingers and toes; a broad, depressed nasal bridge; anteverted nostrils; prominent upper lip; coarse, profuse scalp hair; pilonidal sinus; and simian crease of the left hand. At the age of 7 months, ossification of the distal phalanges of both middle fingers appeared, the anterior fontanel was small, brain development was retarded, cranial asymmetry was marked, and the fingertips showed a pattern of low arch dermal ridges.