In order to study the effect of tantalum on the structure and properties of the complex carbides (Ti, W, Ta) C, the authors prepared solid solutions (Ti, W, Ta) C with the molar concentration ration TiC: WC = 64:36 (35:65 by weight). It is shown that the electrical resistivity of the alloys decreases with increasing amount of tantalum carbide, i.e., the electrical conductivity increases. This is caused by the increased concentration of the conducting (free) electrons and the increased Me-Me bond strength. Alloying with tantalum considerably changes the physicomechanical properties of the carbide constituent of th hard metals, viz., the (Ti, W, Ta) C solid solution. The concentration of the dissolved tungsten and titanium in the cobalt phase is determined by the carbon content in the alloy.