To provide a process for preparing a polyurethane foam, which can exclude the concurrent use of a blowing agent of a fluorocarbon and/or a chlorocarbon and a conventional amine catalyst.

In odder to prepare a polyurethane foam, at least one carbamate represented by formula I: (wherein R1 and R2 are the same or different alkyl groups; R3 and R4 are the same or different groups and are each hydrogen or an alkyl group; R5 is hydrogen, an alkanol group, a polyether monool group or a group represented by X; and (n) is 2 or 3) is used as a catalyst and at the same time as a blowing agent.