The craniofacial characteristics of two syndromes commonly associated with Robin sequence were compared for 49 subjects. Lateral cephalograms were analyzed for four groupings: Group I--Stickler syndrome with versus without Robin, Group II--velocardiofacial (VCF) syndrome with versus without Robin, Group III--Stickler without Robin compared to VCF without Robin, and Group IV--Stickler with Robin compared to VCF with Robin. Thirty-two skeletal and 18 soft tissue measurements were compared. In Group I, three skeletal measurements were significantly different (SNA, SNB, and SNPg). In Group II, no significant difference was found for any of the 50 measurements. In Group III, a significant difference was demonstrated for seven parameters (one skeletal, six pharyngeal and airway). In Group IV, two skeletal and eight airway measures were significantly different. The findings indicate that the relative maxillary and mandibular retrognathia observed in Stickler/Robin patients may predispose them to the Robin sequence and vice versa; the Robin features in VCF may be caused by hypotonia rather than any craniofacial or physical obstruction of the airway; Stickler and VCF are similar in craniofacial morphology but show marked differences in pharyngeal and airway morphology; and cephalometrics should not be the sole prognosticator of the Robin sequence and its association with Stickler and VCF.