Combinations of gelatinous elastomer and polyurethane foam may be made by introducing a plasticized A-B-A triblock copolymer resin and/or an A-B diblock copolymer resin into a mixture of polyurethane foam forming components including a polyol and an isocyanate. The plasticized copolymer resin is polymerized to form the gelatinous elastomer in-situ while simultaneously polymerizing the polyol and the isocyanate to form polyurethane foam. The polyurethane reaction is exothermic and can generate sufficient temperature to melt the styrene-portion of the A-B-A triblock copolymer resin thereby extending the crosslinking and in some cases integrating the A-B-A triblock copolymer within the polyurethane polymer matrix. The combination has a marbled appearance. The gel component has higher heat capacity than polyurethane foam and thus has good thermal conductivity and acts as a heat sink. Another advantage of in situ gel-foam is that the gel component provides higher support factors compared to the base foam alone.