Purpose: As dental implants have become routine therapy, clinicians are more frequently being faced with treating peri-implantitis. To date, no single treatment protocol has been shown to be the preferred means to treat peri-implantitis. The aim of this retrospective case series is to present a novel approach utilizing porcine collagen-coated bovine bone (CBB) to treat peri-implantitis. Materials and Methods: Eleven patients, with no history of periodontitis, presenting with peri-implantitis around a single restored dental implant, were included in the study. At initial and follow-up examinations, bleeding on probing (BOP), probing depth (PD), and gingival margin location (GM) were recorded. Following surgical debridement of the peri-implant defect and treatment of the implant surface with a 0.12% chlorhexidine gluconate solution, bony defects were grafted with CBB. All patients had 12 months of follow-up. Results: Upon presentation, average PD at the deepest site (DS) was 7.6 ± 1.9 mm. At the time of surgery, excess cement was found around nine implants (81%). All patients healed uneventfully without postoperative complications. At 6 and 12 months, all implants showed favorable results with average DS PD reduction of 3.9 ± 1.5 mm and 4.1 ± 1.6 mm, respectively. All implants showed radiographic signs of bone fill, while GM showed no changes from preoperative measurements at either 6 (0.1 ± 0.5 mm) or 12 (0.0 ± 0.6 mm) months. Conclusion: The use of a porcine collagen-coated bovine bone graft to treat peri-implantitis represents a potentially predictable therapeutic modality. Randomized controlled trials are necessary to substantiate the treatment outcomes. Keywords: alveolar bone loss, bone regeneration, bone substitutes, dental implants, peri-implantitis