Purpose: The purpose of this study was to evaluate the effects of phosphated titanium and enamel matrix derivatives (EMD) on osteoblast function. Materials and Methods: Primary rat osteoblasts were cultured on disks of either phosphated or nonphosphated titanium. In half of the samples 180 µg of EMD was immediately added. The medium was changed every 2 days for 28 days and then analyzed using transforming growth factor-b1 (TGF-b1) and interleukin-1b (IL-1b) enzyme-linked immunosorbent assays (ELISAs). Scanning electron microscopy and light microscopy were used to evaluate nodule formation and mineralization. Results: Microscopic evaluation revealed no differences in osteoblast attachment between the 4 groups. Osteoblast nodule formation was observed in all groups. In the absence of mineralizing media, nodules on the nonphosphated titanium samples showed no evidence of mineralization. All nodules on the phosphated titanium had evidence of mineralization. ELISA revealed no significant differences in IL-1b production between any of the groups. The EMD-treated osteoblasts produced significantly more TGF-b1 than non-EMD-treated cells for up to 8 days, and osteoblasts on phosphated titanium produced significantly more TGF-b1 at 8 days. Discussion and Conclusion: Osteoblast attachment appeared unaffected by surface treatment. EMD initiated early TGF-b1 production, but production decreased to control levels within 10 days. Phosphated titanium increased TGF-b1 production at 8 days and induced nodule mineralization even in the absence of mineralizing medium. Schlagwörter: enamel matrix derivatives, interleukin-1b, osteoblasts, phosphate titanium, transforming growth factor-b1