An electrochemical method of producing nanograined hydroxyapatite coatings on titanium surface is reported in this article. The electrolyte contained Ca(NO3)2 and NH4H2PO4 in the molar ratio of 1.67:1. The electrolyte had physiological pH and was ultrasonically agitated throughout the time of electrolysis. Coatings were deposited for 30 minutes at 10 and 15 mA/cm2 and contained monohydroxyapatite phase whose grain sizes were 18 and 25 nm, respectively. These sizes are comparable with the grain size of bone. Small globules of hydroxyapatite covered the coating surface completely. Cell viability and total protein assay studies were carried out using SaOS-2 human osteoblast-like cell line. Of the two, the coating produced at 10 mA/cm2 showed higher viability and protein activity and seems to be a promising material for osseointegration. © 2008 Wiley Periodicals, Inc.