Abstract 1. 1. Some of the definitions of cerebral palsy accepted in this paper do not exclude hereditary and familial cases. 2. 2. Prenatal causes are occupying a steadily growing part in the etiology of cerebral palsy syndromes. 3. 3. Among 120 thoroughly examined patients with cerebral palsy there were 16 children (8 families) with near relatives affected; in 5 of the families consanguinity of the parents was found. 4. 4. Familial and probably genetic factors play, therefore, a certain role in the etiology of cerebral palsy. 5. 5. This fact may have some practical implication for rehabilitation as well as eugenic considerations.