Bisphenol-A is widely used as a component of monomers for resin-based composites and sealants used in dentistry. Bisphenol-A can leach in the surrounding tissues after digestion of the unpolymerized resin monomers with esterase and has the potential to cause irritation, inflammation, and an allergic response. Hence, we examined the adverse effects of bisphenol-A using human dental pulp cells (D824 cells). Bisphenol-A reduced the growth and recover rates of D824 cells. It also decreased the rate of incorporation of [³H] proline into acid-insoluble fractions and the expressions of mRNA and protein for bone sialoprotein. Our findings indicate the possibility that bisphenol-A affects the growth and differentiation of human dental pulp tissue.