Objectives: We aimed to evaluate the clinical and radiological outcomes of open reduction and internal fixation augmented with calcium phosphate cement (CPC) in the treatment of depressed tibial plateau fractures.Methods: Twenty-eight knees of 28 patients [19 males and 9 females; mean age, 41.2 years (range 22-72 years)] who had open reduction and internal fixation combined with CPC augmentation were included in this study. Seventeen fractures were Schatzker type II, 5 were type III, 3 were type IV, 2 were type V, and 1 was type VI. CPC was used to fill the subchondral bone defects in all knees. Fixation of the fragments was done with screws in 3 knees (10%). Standard proximal tibial plates or buttress plates were used in 25 knees (90%) with an additional split fragment extending distally to achieve internal fixation. Full weight-bearing was allowed in 6.4 weeks (range 6-12 weeks) after surgery. Resorption of CPC granules was defined as the decrease in the size and density of grafting material on radiographs. Rasmussen's radiological and clinical scores were determined postoperatively. Functionality was assessed with Lysholm knee scoring system. Activity was graded with Tegner's activity scale.Results: Union was achieved in all patients with a mean follow-up of 22.2 months (range 6-36 months). There were no intraoperative complications. At the latest follow-up radiographs, resorption of the graft was observed in 25 knees (89%). Rasmussen's radiologic score was excellent in 17 patients (61%), good in 9 patients (32%), and fair in 2 patients (7%). Rasmussen’s clinical score was excellent in 9 patients (32%), good in 18 patients (64%), and fair in 1 patient (4%). According to the Lysholm knee score, functional results were excellent in 16 patients (57%), good in 8 patients (29%), and fair in 4 patients (14%). Twenty-two patients (78%) achieved the preoperative activity level after surgery, and there was no significant difference between the mean preoperative and postoperative Tegner scores (4.11±0.68 and 4.04±0.64, respectively, p=0.161).Conclusion: CPC is a safe biomaterial with many advantages in augmenting the open reduction and internal fixation of depressed tibial plateau fractures, including elimination of morbidity associated with bone graft harvesting, the unlimited supply of bone substitute, the optimum filling of irregular bone defects, and shortening of the postoperative full weight-bearing time.