Abstract: The present invention relates to a process for the production of fluorocarbon-free, rigid polyurethane foam moldings having a gross density of at least 300 kg/m.sup.3 by in-mold foaming of a reaction mixture based on(a) a polyisocyanate component containing at least one aromatic polyisocyanate,(b) a polyhydroxyl component,(c) blowing agents,(d) catalysts and(e) zeolitic adsorbents,at an isocyanate index of about 75 to 150, characterized in that(b) an organic polyhydroxyl compound or a mixture of organic polyhydroxyl compounds having an (average) hydroxyl functionality of at least 2.2 and an (average) OH number of at least 300 mg KOH/g is used as the polyhydroxyl component,(c) water and/or carbon dioxide is/are used as the blowing agent and(e) the zeolitic adsorbents have a pore diameter of at least 0.7 nm.