Purpose: The objective of the present study was to clinically and histologically evaluate the effectiveness of deproteinized bovine bone as the augmentation material in vertical ridge augmentation of the inserted implants. Materials and Methods: This retrospective study was performed on 10 vertically augmented ridges in which 24 dental implants were inserted. Deproteinized bovine bone (Bio-Oss) was used as the only augmentation material and was covered with a titanium-reinforced expanded polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex). For 3 augmented areas, bone samples were retrieved for histologic and histomorphometric examination. Results: Clinical evaluations showed bone defects around the implants of 2 to 9 mm (average -5.1 mm; SD = 2.1). Bone height gain at 6 to 8 months after augmentation was 3 to 9 mm (average 5.3 mm; SD= 1.7). Differences between pre- and postaugmentation were statistically significant, for a mean value of > 4 mm (P .005). The obtained bone biopsy specimens showed significant new bone formation and remodeling of the deproteinized bovine bone material. The radiographic data and the clinical stability showed that all implants were successfully osseointegrated. The radiographic and clinical follow-up indicated that the generated bone crest levels were stable. Conclusion: This clinical study suggests that vertical ridge augmentation with an e-PTFE membrane and deproteinized bovine bone is predictable and can lead to long-term success. Keywords: barrier membranes, bovine bone matrix, vertical ridge augmentation