Cobalt based composites with tungsten carbide, titanium carbide and tantalum carbide as a hard phase dispersed finely in the cobalt matrix by mechanical alloying process in high energy ball mill have been investigated. These alloys consist in 90 wt% hard phase and cobalt as a liquid phase activator. Using liquid phase sintering at nearby 1400 degreesC, relative densities of 99% have been achieved, providing best wear behavior and mechanical properties by this process. It is shown that the ball milling time required for highest sintered density is heavily dependent on the milling conditions. The general advantage of this class of material is the simple and robust manufacturing process combined with superior properties.