The growth mechanism of Ti(C,N) coatings produced by chemical vapor deposition was investigated as a function of the TiCl4/CH3CN molar ratio in excess of H-2. The depositions were carried out at a total pressure of 8 kPa, using single crystalline (0 0 l) alpha-Al2O3 substrates. The Ti(C,N) coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The investigated coatings were between 6 and 13 mu m thick. The reaction orders of TiCl4 CH3CN were determined to 0 and 1, respectively, showing that CH3CN is the rate-determining reactant. The preferred orientation of the deposited Ti(C,N) was investigated, showing that molar ratios TiCl4 /CH3CN higher than 2.5 lead to < 2 1 1 >/< 3 1 1 > oriented coatings. A formation mechanism for the < 2 1 1 >/< 3 1 1 > orientations is suggested. Such high ratios lead to the formation of Ti {1 1 1} twinning planes, which provide surface sites that can facilitate fast dissociation of the strong cyanide bond, and thereby cause faster growth in the < 2 1 1 >/< 3 1 1 > directions. Coatings deposited at lower molar ratios show a pronounced < 1 1 1 > out-of-plane orientation, characterized by a {1 1 1} rocking curve yielding values for full width at half maximum (FWHM) below 0.5 degrees.