Introduction: Titanium and its alloys have been widely used as implant materials in orthopedic and dental prosthesis for their excellent biocompatibility, high corrosion resistance, low-weight, and favorable mechanical features. However, the bone ingrowths properties and implant fixation behavior need to be improved to shorten the implant–tissue osteointegration time. Among the available bioceramics to produce coatings, hydroxyapatite [HAP: Ca10(PO4)6(OH)2] is given preference because of its chemical, structural, and biological similarities with natural bone and its direct bone bonding capability with the surrounding tissues. The clinical use of HAP as a load-bearing implant is limited because of its mechanical brittleness and low tensile strength. Therefore, to widen the applicability of HAP to the sites bearing substantial load such as dental or hip implants, a composite system includes HAP coating on metallic implants. This system combines the mechanical advantages of the underlying substrate and biological affinity of the HAP surface to natural tissue. Among a lot of deposition techniques of HAP coating, electrochemical deposition has recently attracted considerable attention because of advantages of the method, such as a low process temperature, the ability to deposit on porous or complex shapes of substrate, the simple control of deposit thickness. The adhesive strength of HAP coating produced by electrochemical deposition is, however, much lower than that of produced by another method. This major drawback restricts the usage of the electrochemical technique. Polyvinyl alcohol (PVA) is added to the electrolyte during the deposition process in order to improve the adhesion strength of electrochemically deposited HAP coating. Experimental procedure: CaP coatings produced on titanium alloy were synthesized by potentiostatic deposition in 1.05mM Ca(NO3)2 and 0.625mM NH4H2PO4 solution at constant deposition time with various amounts of polyvinyl alcohol (PVA) addition. PVA was added into electrolyte in order to improve the adhesion between coating and titanium substrate. The surface morphology and chemical composition of the coatings were characterized by using scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectra (FTIR). Adhesion properties of the deposited layers onto the substrate were investigated by using scanning scratch tester. Result and discussion: In all the coatings produced, it was found that the phases formed are HAP and independent of PVA addition. Thickness of coatings deposits under constant potential with PVA addition was found to increase with increasing time. [Copyright &y& Elsevier]