AIM: The aim of the present study was to evaluate the efficacy of probiotics as an adjunct to scaling and root planning (SRP) in the treatment of chronic periodontitis (CP). METHODS: The focused question of the study was: Does adjunctive use of probiotics yield better clinical periodontal outcomes compared to placebo/no treatment group in the treatment of CP? Electronic and manual literature searches were conducted up to December 2017 using the following databases: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register. Forest plots were computed reporting weighted mean difference (WMD) of outcomes and 95% confidence intervals (CI). RESULTS: Seven clinical studies were included. Four studies showed additional benefits in reducing periodontal probing depth (PPD) and gaining clinical attachment level (CAL), whereas, three studies showed comparable clinical periodontal outcomes between probiotics and SRP/placebo. Significant heterogeneity was observed for PPD reduction and CAL gain. The overall mean difference for CAL gain between probiotics and placebo/SRP was significant (WMD = 1.41, 95% CI = 0.15-2.67, P = .028) at follow up. CONCLUSION: Adjunctive probiotics could result in additional benefits in CAL gain in CP. Nevertheless, further high-quality randomized clinical trials with microbiological outcomes are warranted to obtain strong conclusions in this regard.