The effect of SiC additions on the mechanical properties of TiC films was investigated. Ti-Si-C films with varying SiC content were deposited using dual-cathode radio-frequency magnetron sputtering. The nanoindentation hardness of these films increased with SIC content to a maximum of 20-22 GPa for films in the range of 15-30 at,% SiC. The elastic modulus was also measured, and the hardness to modulus ratio (H/E) increased with SiC content, indicating that hardness increases were due to microstructural effects. The residual stress,vas measured in several films, but was low in magnitude, indicating that hardness measurements were not influenced by residual stress. TEM examination of several films revealed that the SiC additions altered the film microstructure in a manner that could account for the observed hardness increases.