OBJECTIVE To compare the outcome of the trephine with open hip surgery for alveolar bone grafting in cleft lip and palate surgery. DESIGN The study was retrospective. The radiographs were assessed blindly and on two separate occasions 1 week apart. SETTING University Teaching Hospital. PATIENTS, PARTICIPANTS In one group (group A), a trephine was used; in the other (group B), open hip surgery was employed. Group A was comprised of 16 patients (nine with unilateral and seven with bilateral clefts of the lip and palate) and group B, 13 patients (eight unilateral and five bilateral). The prime entry criterion for inclusion in the study was that the canine tooth had erupted into the graft site. INTERVENTIONS A long cone periapical radiograph was taken of the erupted canine tooth in the graft site. MAIN OUTCOME MEASURE The radiographs were graded from type I to type IV, as described by Bergland et al. (1986a). A comparison was also made of the eruption of the canine, postoperative morbidity, and length of stay in hospital for each group. RESULTS There was no statistically significant difference in the interdental bone height (p=.61, Mann-Whitney U test). In group A, all patients had a satisfactory clinical outcome (type I or II), and in group B, only one patient had an unsatisfactory result (type III). The spontaneous eruption of the canine and the number of nights spent in the hospital were also similar for both groups. However, no patients in group A suffered postoperative complications, whereas three patients in group B reported either a limp or postoperative infection of the hip. CONCLUSION Both techniques produced satisfactory repair of the bony defect, but the open hip surgery resulted in greater postoperative morbidity.