We examined blood compatibility of titania gels prepared through a sol-gel processing or yielded on titanium substrates by treating with hydrogen peroxide or simple heating. The blood compatibility was evaluated in terms of blood clotting time and correlated to the crystalline phases, roughness, specific surface area, and wettability. The sol-gel derived titania gel heated above 200°C had good blood compatibility. Ti substrate treated with hydrogen peroxide and subsequently heated at 550°C showed the best blood compatibility among the Ti substrates with or without the chemical treatment and heat-treatment. The specimen consisted of rutile and anatase phases, and had hydrophilic surface.