We report on 2 boys, the sons of sisters, and their mother's brother who have a new, X-linked multiple congenital anomalies/mental retardation (MCA/MR) syndrome. The propositus was a 16-month-old caucasian male with 1) mental retardation, 2) congenital microcephaly, 3) postnatal growth deficiency, 4) ridged metopic suture with narrow bifrontal diameter, 5) upslanted palpebral fissures with persistent epicanthal folds, strabismus, and lacrimal duct obstruction, 6) narrow palate, 7) macrodontia, 8) anteverted ears, 9) atrial septal defect, 10) dry brittle scalp hair and 11) cutis marmorata. His chromosomes were normal. His cousin and uncle were similarly affected. This distinctive MCA/MR syndrome is added to the list of X-linked malformation syndromes known at the present time.