OBJECTIVE The purpose of this study was to evaluate the gingival fibroblast proliferative response derived from patients with chronic and aggressive periodontitis to homologous platelet-rich plasma (PRP). METHODS Gingival fibroblasts derived from nine patients with chronic periodontitis, aggressive periodontitis and healthy periodontium were grown. Medium was replaced with DMEM containing 0.5% FBS in which cells remained for two days. Cells were incubated and cultured with medium containing 50 microl/ml homologous platelet-rich plasma (PRP) or not containing PRP (control) for 24 and 48 hours. PRP originated from three donors. Cell proliferation effect was evaluated at 24 and 48 hours. Cell viability was assessed with a hemocytometer. Viable cells were counted under a phase contrast microscope. RESULTS The results revealed that incubation of human gingival fibroblasts, derived from healthy and intact periodontium, chronic periodontitis and aggressive periodontitis, in culture medium containing homologous PRP statistically significantly increased the cell proliferation at 24 and 48 hours of culture. CONCLUSIONS The addition of PRP to human gingival fibroblast cultures significantly increased the proliferative response, irrespective of the presence of periodontitis, type of periodontitis and PRP donor.