The high-durability flexible polyurethane cold cure molded foam of the invention has an overall density of not less than 35 kg / m3 and not more than 45 kg / m3 and a wet heat compression set of not more than 15%, and preferably has a hardness change ratio, as determined in a repeated compression test, of not more than 15%. This foam can be obtained by the process of the invention. The process of the invention is a process for producing a flexible polyurethane cold cure molded foam obtained from a polyol and / or a polymer polyol containing dispersed polymer microparticles obtained by radical polymerizing a compound having an unsaturated bond in the polyol, water, a catalyst and a polyisocyanate, wherein the polyol is a polyol synthesized by the use of a catalyst containing at least one compound selected from the group consisting of a compound having a nitrogen-phosphorus double bond, cesium hydroxide and rubidium hydroxide. The foam of the invention has a low density and is excellent in durability, particularly in hardness change ratio in a repeated compression test and wet heat compression set. According to the process of the invention, such a foam can be obtained.