Objective. Periodontal regeneration is histologically defined as regeneration of the tooth supporting structures, including alveolar bone, periodontal ligament, and cementum. Cells in the remaining periodontal tissues need optimal conditions if they are to perform their functions in the regeneration process. The present study is an investigation of the molecular effects of ABM/P-15 on human periodontal ligament cells (PDL) in vitro. Material and methods. PDL cells obtained from healthy subjects were used for in vitro experiments. Cell proliferation, morphology, and mineralization using Von kossa staining were evaluated. mRNA expressions for transforming growth factor-β (TGF-β), insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (b-FGF), vascular endothelial growth factor (VEGF), bone morphogenic protein-2 (BMP-2), platelet-derived growth factor (PDGF), and type 1 collagen (COL1) were assessed on days 3 and 7 using RT-PCR. Results. ABM/P-15 enhanced proliferation of cultured PDL cells. It increased the mRNA expression of TGF-β and BMP-2 in cultured PDL cells on days 3 and 7. IGF-I and b-FGF mRNA expressions showed a slight decrease, while PDGF expression was observed to have increased on day 3. VEGF and COL1 mRNA expressions were found not to be different on days 3 and 7. No differences were observed in the mineralization properties of cultured PDL cells treated with or without ABM/P-15. Conclusions. Based on the results of this in vitro study, it may be concluded that ABM/P-15 enhanced the regenerative capacity of PDL by regulating specific gene expressions of cells during early wound healing. © 2009 Informa UK Ltd. (Informa Healthcare, Taylor & Francis As).