PURPOSE: Achieving implant primary stability in poor-density bone is difficult when the available bone height is less than 6 mm. This study assesses the 1-year clinical performance of tapered implants in sites of reduced height in combination with osteotome sinus floor elevation without bone grafting material. MATERIALS AND METHODS: An osteotome sinus floor elevation procedure without grafting material was performed in the atrophic posterior maxilla. Tapered implants were placed in maxillary sites with residual bone height of 1 to 6 mm. Implant primary stability was assessed by finger pressure exerted on the implant. Bone gain in the elevated sinus and crestal bone loss were evaluated at 1 year via radiographs. RESULTS: Fifty-four tapered implants were placed in 32 patients and were loaded after a mean of 4.2 +/- 1.6 months. The mean maxillary residual bone height was 3.8 +/- 1.2 mm. All implants achieved primary stability, and all were successfully loaded. At the 1-year radiographic control, the mean bone gain within the sinus was 2.5 +/- 1.7 mm and the mean crestal bone loss was 0.2 +/- 0.8 mm. CONCLUSIONS: In the atrophic posterior maxilla, primary stability can readily be achieved with tapered implants, even when the mean residual bone height is 3.8 mm. Despite limited bone support and lack of grafting material, all loaded implants were clinically stable, and crestal bone loss was limited. A net bone gain of 2.3 +/- 1.8 mm was observed. Survival and success rates were 100% and 94.4%, respectively. Elevation of the sinus membrane without the addition of bone grafting material led to bone formation beyond the original limit of the sinus floor.