An important issue facing most dental clinicians is whether the bone replacement grafts help in preserving alveolar bone in post-extraction period, and whether they will limit or reduce alveolar bone height's shrinkage, when compared to sites not receiving a graft material. The aim of this study was to compare post-extraction vertical bone loss between two groups using cone beam computerized tomography (CBCT), where one group received Osteobiol Gen-Os® (xenograft) and CollaPlug® (collagen sponge) and the other group only received CollaPlug®. Material and Methods: Fourteen patients requiring tooth extraction were enrolled in the study. They were divided in two groups: Group I (study -or test- group of seven patients who received Osteobiol Gen-Os® and CollaPlug®), and Group II (control group of seven patients who only received CollaPlug® in extraction sites). Vertical alveolar ridge changes were studied on CBCT images, in the two groups, from time of extraction to four months following extraction. Results: Vertical bone loss was significantly less in test group (0.66 ±0.071 mm) compared to control group (0.967±0.13 mm). Conclusion: In alveolar ridge preservation, the use of xenograft in conjunction with a collagen sponge is more efficient than the sole use of a collagen sponge, in a fresh extraction socket.