A severely retarded male infant was found to have a previously undescribed multiple congenital anomalies/mental retardation (MCA/MR) syndrome including microdolichocephaly, prominence of metopic suture, coarse scalp hair, epicanthus, anteverted nostrils, micrognathia, posteriorly angulated malformed auricles, preaxial hexadactyly, clinodactyly, camptodactyly, hypospadias, cryptorchidism, inguinal hernias, agenesis of left kidney, and pyloric stenosis. This syndrome was due to an interstitial del(1)(q25.2q31.2) associated with a paracentric inv(1)(q31.2q44).