This study was undertaken to evaluate the stability of maxillary advancement using bone plates for skeletal stabilization and porous block hydroxyapatite (PBHA) as a bone graft substitute for interpositional grafting in cleft and non-cleft patients. The records of 74 patients (41 females, 33 males) who underwent Le Fort I maxillary advancement using rigid fixation and PBHA interpositional grafting were evaluated retrospectively. All patients also underwent simultaneous sagittal split mandibular ramus osteotomies. Patients were divided into 2 groups for study purposes: group 1 consisted of 17 cleft palate patients and group 2 consisted of 57 non-cleft patients. Each group was further subdivided into 2 subgroups based on the concurrent vertical positioning of the maxillary incisors: groups 1a and 2a, where the maxilla underwent 3 mm or more of inferior repositioning, and groups 1b and 2b, where the maxilla underwent minimal vertical change (< or = 1 mm). Presurgery, immediate postsurgery, and longest follow-up lateral cephalometric tracings were superimposed and analyzed to calculate surgical change and long-term stability of results by assessing horizontal and vertical changes at point A, incisor superius, and the mesial cusp tip of maxillary first molar. The average follow-up time in group 1 was 37.9 months (range 12 to 136) and in group 2 was 28.77 months (range 17 to 88). Average maxillary advancement at point A was: group 1a, 5.4 mm; group 1b, 5.25 mm; group 2a, 5.48 mm; group 2b, 5.46 mm. Average relapse at point A was: group 1a, -0.75 mm; group 1b, -1 mm; group 2a, -0.47 mm; group 2b, -0.48 mm. Average horizontal and/or vertical relapse at the central incisors and first molars was 1 mm or less in group 1 and less than 0.5 mm in group 2. Although there was a slightly greater relapse in group 1, no statistically significant difference was observed between the groups. Maxillary advancement with Le Fort 1 osteotomies using rigid fixation and interpositional PBHA grafting during bimaxillary surgery is a stable procedure with good predictability in cleft and non-cleft patients, regardless of the direction of vertical maxillary movement.