Purpose: To evaluate changes in sinus dimensions immediately postoperatively and 1 year later using a composite of bovine-derived xenograft and autogenous bone for lateral bone augmentation of the maxillary sinus. Materials and Methods: Patients who underwent lateral wall sinus augmentation procedures without concomitant implant placement were considered for this retrospective analysis if they had three consecutive panoramic radiographs: pretreatment (T0), immediately after lateral wall sinus augmentation (T1), and approximately 1 year postoperatively (T2). Eighteen subjects aged 47 to 69 years were included. The surgical protocol included grafting with a composite of bovine-derived xenograft and autogenous bone (9:1 ratio). Digital panoramic radiographs were transferred into measurement software, and the following measurements were performed: (1) vertical distance from the alveolar crest to the height of the augmented material, (2) sagittal area of the grafted area, and (3) vertical distance from the alveolar crest to the roof of the maxillary sinus. All measurements were performed by one examiner. Double measurements were performed in nine patients at T2, and the calculated Cronbach's alpha statistic was very high (.9658 to .9882). Results: The mean overall sinus sagittal area was 1,330 ± 481 mm2 prior to the grafting procedure, when it decreased to 858.2 ± 436 mm2 (range, 380.7 to 2,134 mm2) immediately postoperatively (P = .0035) and remained stable at 1 year (mean, 882.2 ± 384 mm2, P > .05). Similarly, the overall area of the grafted material at the time of surgery was 468.3 ± 208 mm2 and was only slightly reduced at 1 year (422.2 ± 193 mm2). The midsagittal graft height at T1 (mean, 20.67 ± 4.5 mm) was insignificantly and minimally reduced at 1 year (mean, 19.35 ± 4.9 mm). Conclusion: The linear dimensions of composite bone-derived xenograft/autogenous bone grafts following lateral wall sinus augmentation exhibited minimal changes during the 8- to 12-month healing period. Keywords: autogenous, lateral wall, radiographic measurements, sinus augmentation, xenograft