Secondary bone grafting of the maxilla in the mixed transitional dentition stage has become a well-accepted procedure in the surgical protocol for rehabilitation of patients with residual alveolar clefts. This retrospective study was undertaken to evaluate and compare the longterm results obtained with iliac or cranial cancellous bone graft material in the area of alveolar clefts and was based on the independent experience of two plastic surgeons from the same center using exclusively cranial or iliac cancellous bone, respectively. The criteria for surgery were similar. The surgical technique, with the exception of the bone-grafting material, also was similar, and all patients were treated by the same group of orthodontists. Fifteen patients from each group, from a total of over 100 patients, were randomly selected and included in the study. All patients were followed up from 18 to 60 months. Operative and perioperative parameters, donor-site morbidity, and long-term results were evaluated, compared, and analyzed. There were no significant differences between the two groups, and equally good results in terms of bone incorporation, tooth eruption, and appearance were obtained with both iliac and cranial bone grafts. We conclude from our study that successful bone grafting is primarily achieved by adherence to meticulous surgical technique, simultaneous closure of coexisting oronasal or palatal fistulae, use of cancellous bone particles only, and coverage of the grafts with well-vascularized flaps. The source of bone graft does not seem to primarily influence the success of the outcome.