Protein thin films were prepared by electrostatic spray deposition (ESD) from aqueous solutions of the enzyme alkaline phosphatase (ALP). ALP thin films with preserved functional properties were successfully deposited using the ESD technique. The biological activity of the deposited ALP films was investigated in vitro by immersing the ESD-coated titanium substrates in both simulated body fluid (SBF) and cell-culture medium. Mineral deposition occurred on substrates immersed in both SBF and medium. Various analytical techniques (SEM,XRD,FTIR,EDS) showed that the calcium phosphate layers deposited in SBF and medium differ in both crystallinity and morphology. The results demonstrated that ESD is a successful method for the deposition of biomedical coatings with enhanced functionality.