Purpose: The objective was to compare implants in the posterior maxilla with or without sinus floor augmentation. Materials and Methods: A retrospective study was conducted of patients who received implants in the posterior maxilla. All patients received solitary, implant-retained fixed partial dentures or crowns. A standardized form for implant treatment was used to document the follow-up examination. The different parameters were initially analyzed descriptively by frequency distribution, measure of central tendency, and statistical spread. A 95% level of significance was set for all tests. Results: A total of 76 patients with 141 dental implants in the posterior region of the maxilla were evaluated. Fifty-one patients with 71 implants received prior no augmentation (sinus floor elevation) and composed the control group. Twenty-five patients with 70 implants received an additional bone transfer prior to implant placement. The mean age of the patients at time of the follow-up examination was 49.7 years in the overall group, 52.6 years for men and 46.7 years for women. The implants inserted in an augmented area had similar implant stability and implant loss results after a mean functional observation period of 1.6 years (range, 0.5 to 4.7 years) compared to those inserted without augmentation. Augmented implants exhibited less peri-implant bone resorption. Conclusions: The outcomes for implants with augmentation were similar to those without augmentation. (Comparative Cohort Study) Schlagwörter: comparative study, peri-implant bone resorption, posterior maxillary region, sinus floor elevation