Disclosed is an isocyanate-reactive composition comprising an isocyanate-reactive compound having an equivalent weight of from about 400 to about 12000, and a stabilizing amount of methyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate with optional costabilizers selected from another phenolic, an amine, a phosphite, a thioether, or a lactone stabilizer to form a stabilizer package which may be further used in a process for preparing a flexible polyurethane foam comprising reacting together an organic polyisocyanate with an isocyanate-reactive composition in the presence of a blowing agent to form the polyurethane foam.