The thermal stability of the machining centers plays a major role in ensuring the production repeatability. All machine tools producers take various steps to ensure it. One of the ways to permanently maintain and stabilize the behavior of the machine tool is the use of active cooling and the choice of appropriate material of which the individual parts of the supporting system are made. In most cases, manufacturers of the machining centers use traditional metallic materials (steel, cast iron) for construction of the machine supporting system. However, these materials have some physical limitations. These materials can be replaced by or combined with unconventional materials to improve the thermal stability of the machine. The hybrid composite supporting structures are formed this way. The authors of this article examine the impact of steel-concrete composite material on thermal-deformation behavior of the bed in a vertical turning machining center for medium-heavy workpieces. The composite consists of the steel weld, filled with high-strength concrete.