This cephalometric study reports the extent to which maxillary growth may be impaired by grafting of alveolar bone during the period of mixed dentition. The analysis is confined to subjects with unilateral cleft lip and palate (UCLP). The craniofacial dimensions of a group of 28 children who underwent grafting before the age of 12 years were compared by t-test to those of a nongrafted group (N = 30) at 9 and 16 years of age. In addition, two multiple-regression analyses were performed, the second on a group of 70 subjects with UCLP who received a bone graft between the ages of 8 and 15 years. The principal finding was that bone grafting, even when performed on those as young as 8 or 9 years, had no adverse effect on anteroposterior or vertical maxillary growth. This may be attributable to postponement of grafting until most anteroposterior and transverse growth of the anterior maxilla had ceased and to the grafted tissue's ability to participate in the vertical development of the alveolar process.