The process of the subject invention is directed to the formation of foams, especially flexible foams, by the reaction of a polyisocyanate with a polyol in the presence of one or a mixture of amine compounds of the general formula: ##STR2## wherein R1 is a methyl or ethyl and R2 is hydrogen or methyl such that when R1 is ethyl, R2 is hydrogen and when R1 is methyl, R2 is methyl.