Two types of bicomponent systems for the prodn. of rigid polyurethane foams (high- and low-reactive) were mixed with polystyrene beads (EPS) to obtain 2 polystyrene-polyurethane composites (PSUR). The mixts. were poured into metal mold at room temp. The effect of EPS mass fraction on the PSUR foaming process were examd. by using measurements of temp. and heat flux d. as a function of time. The expansion of EPS occurred already at 50 degrees C in the low-reactive system.