The main goal of sinus augmentation is the formation of vital bone to allow tissue integration of endosseous implants to support prosthetic rehabilitation. The aim of the present investigation was to evaluate the radiographic and histologic results when granular medical-grade calcium sulfate hemihydrate was used as a grafting material in sinuses. Forty implants plus grafting material were placed in 10 patients, representing 15 sinuses, using a one-stage technique. Radiographs were taken prior to sinus augmentation, monthly until 6 months postoperatively, 9 and 12 months after implant placement, and annually thereafter. Bone biopsies were harvested from all patients for histologic and histomorphometric evaluation.