The objective of this experiment was to develop biomimetic calcium phosphate coatings on low-modulus Ti-7.5Mo substrates treated with NaOH aqueous solutions and subsequent water aging before soaking them in simulated body fluid (SBF). Specimens of commercially pure titanium (c.p. Ti) and Ti-7.5Mo were initially treated with 5 M NaOH at 60 A degrees C for 24 h, resulting in the formation of a porous network structure composed of sodium titanate (Na2Ti5O11). Afterward, the specimens were aged in distilled water at 80 A degrees C for 12, 24, or 48 h, and subsequently immersed in 1.5SBF at 37 A degrees C for either 1 or 13 days. The calcium phosphate-forming abilities of the c.p. Ti and Ti-7.5Mo achieved by a single NaOH treatment were low, but were significantly increased by the water aging. The amount of calcium phosphate deposited on the Ti-7.5Mo after NaOH treatment and subsequent water aging for 12 or 24 h was much greater than other conditions. The calcium phosphate-coated Ti-7.5Mo has strong potential as an artificial bone substitute or in other hard tissue-replacement materials with heavy load-bearing requirements due to a favorable combination of bioactivity, low elastic modulus, and low processing costs.