Introduction: One of the consequences of periodontitis is periodontal intrabony defects (PID). Various biomaterials have been used for its treatment, but there is still no biomaterial considered as the gold standard. Current research is focused on the use of platelet-rich plasma (PRP) for the treatment of PID. Objective: To determine the clinical effect of PRP in the treatment of PID through a systematic review with meta-analysis. Materials and Methods: A literature search was conducted until February 2017 in the biomedical databases: Pubmed, Embase, Scielo, Science Direct, SIGLE, LILACS, IBECS, and the Cochrane Central Register of Clinical Trials. The criteria for the selection of the studies, which were randomized clinical trials, were the following: articles or papers published in the last 5 years, reporting clinical effects, with a follow-up time equal to or greater than 6 months, and a sample size equal to or greater than 10 patients reporting the use of PRP as a treatment for PID. The methodological quality of thestudies was analyzed using the Cochrane Handbook of Systematic Reviews of Interventions as a reference. Results: The search strategy yielded nine articles reporting a reduction in probing depth and gingival recession, and an increase in clinical insertion level when using PRP alone or in combinationwith another biomaterial.