Three patients with duplication of 3q regions ranging from 3q25----qter to the entire long arm provide additional documentation of the dup(3q) malformation syndrome. Data on 40 cases now reported define a characteristic face with hirsutism, synophrys, broad nasal root, anteverted nares, downturned corners of the mouth, micrognathia, and malformed ears recognizable even in the 30-week fetus and distinct from that of the Brachmann-de Lange syndrome. Other characteristic anomalies include congenital heart anomalies involving primarily septal defects, hand malformations including simian creases, abnormal dermatoglyphics, clinodactyly or camptodactyly, omphalocele, skeletal anomalies, and genitourinary malformations. Severe mental and growth retardation are common in those patients (64%) who survive the first year. Chromosome study of relatives is extremely important for counseling because only 10 of 40 cases represented de novo duplications.