Tumor necrosis factor-alpha (TNF-α) is an inflammatory cytokine known to cause bone resorption, swelling and edema during tissue organization. Conversely, TNF-α has also been shown to participate in tissue regeneration during the wound healing process. We have previously investigated the effects of TNF-α on human dental pulp cell differentiation. Dental pulp cells are composed of different cell types including primary odontoblasts and fibroblasts. We determined that the ratio of stem cells within the pulp cell population was increased following short-term stimulation with TNF-α. The aim of this study therefore was to investigate the effect of short-term stimulation with TNF-α on osteoblast-like MC3T3-E1 cell growth and differentiation. MC3T3-E1 cells were cultured in standard growth medium and on reaching sub-confluence were exposed to recombinant TNF-α (10 and 100 ng/ml) for 2 days prior to assessing their cell proliferation and differentiation properties in comparison to non-stimulated MC3T3-E1 cells (control). Although no significant differences in cell proliferation were observed between the TNF-α-stimulated and control groups, cell differentiation was delayed in the TNF-α-stimulated groups. In summary, short-term stimulation of cultured MC3T3-E1 cells with TNF-α had only minimal effect on their growth and differentiation.