Increasing osteoblast activity in an anabolic fashion may offer an ideal therapeutic treatment for various orthopedic complications including osteoporosis. The purpose of this study was to evaluate the effect of mevinolin, a clinical statin drug, on osteoblast function (MG 63 Cell Line) and compare its mode of action with the conventionally utilized parathyroid hormone (PTH). MG63 cells were treated with different concentrations (control, low (100 nM), medium (1 uM), and high (10 uM)) of mevinolin or Parathyroid hormone. The cells were incubated for 24, 48, and 72 hours at 37 degrees C in a 95% air and 5% CO2 environmental chamber. Data obtained in this study revealed that: (I) there were significant decreases in cell number after 24 hours upon the exposure of medium and high doses of mevinolin, (II) cell numbers rebounded back toward control after 48 hours and were similar in number at 72 hours, and (III) there were no significant changes in calcium or alkaline phosphatase activity were observed throughout the study. Morphologically, the cells treated with various doses of Mevinolin expressed similar structural changes to those observed using PTH. These changes included pleomorphic characteristics and an occasional hyperchromatic pattern during the entire duration of the study (72 Hours). Other structural features observed were spindle shapes, cluster arrangements and multinucleation. The majority of cells had multiple nucleoli in all treated groups compared to controls. The overall conclusion of this investigation demonstrated that the concentrations used (100 nM and 10 microM) did not appear to affect the mitotic activities of immature phenotypic MG-63 cells. In addition, the concentrations of mevinolin used did not trigger the differentiation process of the cells throughout the experimental phases. This observation led us to suggest that the reason for such an outcome could be attributed to the lack of a response in calcium production or alkaline phosphatase activity (stimulator to differentiation and mineralization process).