The aim of this study was to compare the results of treatment obtained with mandibular symphyseal and iliac crest bone grafts used for reconstruction of alveolar clefts. The study included 40 patients with unilateral cleft lip palate (UCLP): 20 consecutive patients whose defects were reconstructed with mandibular bone grafts (MBG) and 20 randomly selected UCLP patients who underwent reconstruction with iliac crest bone (ICB). The age at surgery varied from 8 to 13 years (mean age MBG group, 9.1 years; ICB group, 10.3 years), and the postoperative observation period varied from 12 to 33 months (mean, 19 months). Transverse expansion of the maxilla was not completed until after the bone grafting in the group of patients receiving MBGs, whereas it was completed before surgery in the ICB group. The observed marginal bone level on cleft-related teeth was similar in both groups. No periodontal complications were present in any of the patients, and the amount of attached gingiva was similar in both groups. In the MBG group, 15% of the canines were retained, whereas 20% of the canines were retained in the ICB group. The only complication that developed was in a patient from the MBG group, in whom a partial dehiscence of the donor site was observed. The results of this study demonstrate that reconstruction of alveolar clefts with MBG or ICB has a comparable prognosis. The use of MBGs in these patients has several advantages compared with ICB, including reduced operating time, reduced morbidity, reduced hospitalization time, and finally, a cutaneous scar at the iliac crest can be avoided.