In this study we investigate the effects of nanotubular titanium oxide (TiO 2 ) surfaces on vascular cells. EC and VSMC response to nanotubes was investigated through immunofluorescence staining, scanning electron microscopy, 5-ethynyl-2′-deoxyuridine proliferation assays, and prostaglandin I 2 (PGI 2 ) enzyme immunoassays. We found that the nanotubular surface significantly enhances EC proliferation and secretion of PGI 2 . The surface also results in a decrease in VSMC proliferation and increased expression of smooth muscle α-actin. These data suggest that engineered nanotopographical cues may influence both EC and VSMC behavior in a manner that may be useful for stent or other vascular applications.