Purpose: To clinically and histomorphometrically compare a biphasic calcium phosphate (BCP) and deproteinized bovine bone mineral (DBBM) for sinus floor elevation. Materials and Methods: Sinus floor elevation procedures (lateral window) were performed randomly applying either BCP (test) or DBBM (control). At 6 months, bone biopsy specimens were harvested and dental implants were placed. The proportions of new bone, residual grafting material, and nonmineralized soft tissue were calculated. Four months after implant placement, the prosthetic reconstructions were inserted and the implant survival was assessed. Results: Fifty-one patients were treated; 25 were randomly allocated to the BCP group and 26 to the DBBM group. After 6 months in 50 patients, bone biopsy specimens could be harvested, and a total of 121 implants could be placed subsequently. The histomorphometric analysis revealed a comparable percentage of new bone in both groups (BCP 35.9%, DBBM 35.4%; P > .05). The remaining grafting material was significantly lower with BCP (25.3%) compared with DBBM (45.9%; P .001). Nonmineralized tissue was significantly higher for the BCP group (38.1%) compared with the DBBM group (18.2%; P .001). The implant survival rate at loading was assessed at the level of the patients (96.0% for BCP and 88.8% for DBBM; P > .05) and at the level of the implants (96.9% for BCP and 94.7% for DBBM; P > .05). Conclusion: Grafting with DBBM or BCP showed similar percentages of new bone 6 months after sinus floor elevation. Implant survival presented no significant difference until loading. Keywords: biphasic calcium phosphate, bone grafting, bone substitute, deproteinized bovine bone, histomorphometry, maxillary sinus, randomized controlled trial, sinus floor elevation