Platelet-rich plasma (PRP) is derived from fresh whole blood, which contains a high concentration of platelets. Recently, PRP has been used for skin wound healing and rejuvenation. However, the molecular mechanisms underlying PRP-inducing wound healing processes are still largely unknown. The aim of this study is to evaluate the effect of PRP on the expression of G1 cell cycle regulatory proteins, type I collagen, matrix metalloproteinase-1 (MMP-1), and MMP-2 in human skin fibroblasts (HSF). We performed a cell proliferation and a migration assay, immunoblotting, and a chloramphenicol acetyltransferase (CAT) assay in PRP-treated human skin fibroblasts. PRP treatment induced increased rates of cell proliferation and cell migration. Expression of cyclin A protein was increased by a low concentration (0.5%) of PRP-treated HSF. In addition, expression of Rb, cyclin E, and cyclin-dependent kinase 4 proteins was increased by a high concentration (5%) of PRP-treated HSF. High concentration of PRP induced an up-regulation of type I collagen, MMP-1, and MMP-2 expression in HSF. Taken together, PRP treatment induced an increase in expression of G1 cell cycle regulators, type I collagen and MMP-1, thereby accelerating the wound healing process.