Thermal oxidation (TO) of Ti6Al4V alloy was performed at 500,650 and 800 degrees C for 8,16,24 and 48 h in air. The morphological features, structural characteristics, microhardness and corrosion resistance in Ringer's solution of TO Ti6Al4V alloy were evaluated and compared with those of the untreated one. The surface morphological features reveal that the oxide film formed on Ti6Al4V alloy is adherent to the substrate at 500 and 650 degrees C irrespective of the oxidation time whereas it spalls off when the alloy is oxidized at 800 degrees C for more than 8 h. X-ray diffraction (XRD) measurement reveals the presence of Ti(O) and alpha-Ti phases on alloy oxidized at 500 and 650 degrees C, with Ti(O) as the dominant phase at 650 degrees C whereas the alloy oxidized at 800 degrees C exhibits only the rutile phase. Almost a threefold increase in hardness is observed for the alloy oxidized at 650 degrees C for 48 h when compared to that of the untreated one. Thermally oxidized Ti6Al4V alloy offers excellent corrosion resistance in Ringer's solution when compared to that of the untreated alloy. (C) 2009 Elsevier B.V. All rights reserved.