Hard coatings based on the multiphase W-Ti-Si-C system have been obtained by combined magnetron sputtering and ion implantation process (CMSII). The coatings have been produced from complex targets having a variable SiC content (5 and 10 wt.-%). Their characterization included chemical and structural analysis by X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES), scanning electron microscopy (SEM) investigation, and microhardness measurements. The coating produced from a target with 5% SiC showed a multiphase structure consisting of W2C, W3C, and WC1 − x phases, whereas the coatings produced from target with 10% SiC revealed a multiphase structure of (W,Ti)C1 − x. The microhardness of the coatings was in the range of 2 250–3 500 HV 0.05. The layers were subjected to oxidation tests performed by heating in air at temperatures up to 920 °C. The microhardness evolution after each cycle of heating was studied.