Binder syndrome or maxillonasal dysplasia is characterized by maxillary hypoplasia and a flat, vertical nose. Inheritance is uncertain. We report on a mother and her son with Binder syndrome. The proband was the last child of a kinship of seven children. Three sisters, three brothers and the parents were normal. The proband had a maxillary hypoplasia and a flat, vertical nose. The columella was short, the nostrils had a triangular shape and the upper lip was convex with an acute nasolabial angle. There were no dental abnormalities apart from those secondary to malocclusion. Height and intelligence were normal. After an uncomplicated pregnancy, the proband delivered a boy who had low nasal bridge, hypertelorism, maxillary hypoplasia and a small nose with a broad columella. Although the majority of cases of maxillonasal dysplasia are sporadic, familial occurrence has been reported by a number of authors. In six pedigrees the recurrence was in second or third degree relatives. Recurrence in sibs with unaffected parents has been observed seven times and an affected parent and child has been rarely reported. The Binder phenotype may be heterogeneous. The pattern of abnormalities seen in this condition does not represent a causally defined entity.