Stabilized polyvinyl chloride molding compositions contain, per 100 parts by weight polymer, 0.02 to 5 parts by weight of at least one compound of Formula I and/or Formula II ##STR1## in which R represents an alkyl group with 1 to 18 carbon atoms, a cycloalkyl group with 5 or 6 carbon atoms, a phenyl group, an alkylphenyl group with 7 to 11 carbon atoms or an X--CO--CH.sub.2 group, while X represents an NH.sub.2 group or an OM group in which M represents lithium, sodium or potassium.