BACKGROUND The question whether a minimal maxillary residual bone height (RBH) allows the predictable use of osteotome sinus floor elevation (OSFE) remains unresolved. PURPOSE To evaluate the efficacy of short implants placed with OSFE in an RBH of ≤4 mm and to compare bone levels around implants placed with (control) or without (test) grafting after 3 years. MATERIALS AND METHODS Eight-millimeter implants were placed by OSFE in sinuses randomized to receive anorganic bovine bone or no grafting material. Healing time before prosthetic rehabilitation was 10 weeks. Peri-implant bone levels were measured on standardized periapical radiographs. RESULTS Thirty-seven implants (17 test, 20 control) were placed at a mean RBH of 2.4 ± 0.9 mm. Three implants failed during the 3-year follow-up. After 3 years, all implants had gained endosinus bone (test: 4.1 ± 1.0 mm; control: 5.1 ± 1.2 mm; p = .001). Mean bone gain was stable between 1 and 3 years in both groups. CONCLUSIONS Grafting is unnecessary to achieve bone augmentation of 4.1 mm; however, more bone is gained with grafting. Bone gained over 1 year was retained. Atrophic posterior maxillae can be predictably rehabilitated using OSFE and simultaneous placement of 8-mm implants.