Aim: To review the literature of adjunctive antimicrobial photodynamic therapy (aPDT) in patients with peri-implantitis. Material and Methods: A systematic review of the literature was conducted according to statement of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and Cochrane Collaboration recommendations. An extensive literature search and a manual search were performed on eight databases and various journals using MeSH terms, keywords, and title words (9th september 2014). Studies were evaluated and summarized in a narrative review. Risk of bias was assessed for each included trial. Cochrane risk bias tool was used to assess each trial on five criteria sequence generation, allocation concealment, blinding, incomplete outcome data and selective outcome reporting. Results: From 123 citations identified and available abstracts screened, 27 full-text reports were assessed and 23 were included in the review. These included 12 over- and review articles and 11 clinical trials (5 prospective trials, 4 RCTs and 2 case studies). Two of the 4 RCTs were identified as continuation of 2 previous RCTs. No meta-analysis could be conducted because of the small number of RCTs with a great heterogeneity. There is insufficient evidence regarding the efficacy of aPDT in peri-implant management due to the small amount of RCT's. No statement can yet be made for additional clinical benefits. Conclusion: According to the present analysis aPDT cannot be recommended for periimplantitis treatment. Further high-quality RCT's are needed to investigate the influence of potential confounders on the efficacy of (adjunctive) aPDT in periimplantitis treatment. Keywords: antimicrobial photodynamic therapy, peri-implantitis, systematic review