The objectlve of this study was to evaluate the response of passivated titanium (Ti) surfaces in the following simulated bioiogical environments; 1) an alpha minimum essential medium (α-MEM), and 2) a rat bone marrow cell culture system. Fourier transform infrared spectroscopy indicated the presence of adsorbed amorphous/fine crystalline calcium phosphate (Ca-P) compounds on Ti surfaces after immersion in α-MEM. X-ray photoelectron spectroscopy revealed a high initial concentration of phosphorus (P) on Ti surfaces as compared to calcium (Ca); resulting in a continuous change in the Ca/P ratio from 0.5 after 3 hours to 1.2 after 12 days in solution. The adsorbed Ca-P compounds on the Ti surfaces exhibited a chemistry more similar to brushite than hydroxyapatite. Initial in vitro cell culture analyses revealed no statistical difference in the cell numbers between the Ti surfaces and the polystyrene tissue culture plates. However, after a 6 days incubation, the polystyrene tissue culture plates exhibited about 32% greater cell number as compared to the Ti surfaces. Furthermore, throughout the 6 day study, cells on both the polystyrene tissue culture plates and Ti surfaces did not exhibit any statistical difference in the amount of protein retained within the cell layer.