This invention relates to a process for the production of polyurethane resins (more particularly foam resins) in which linear polyamines containing at least four tertiary nitrogen atoms are used as catalysts. The compounds correspond to the general formula: ##STR1## wherein the groups R, which may be the same or different, represent methyl or ethyl groups; m represents an integer of from 2 to 7; and the integers n, which may be the same or different, represent 2 or 3.