The invention relates to the use of oligomeric carbodiimides containing at least one heterocyclic end group as stabilizers for polymers. The oligomeric carbodiimides can be compounds of the general formula (I), in which A1, A2 are identical or different and represent hydrocarbon groups with 2 to 20 carbon atoms independently of each other; B1, B2 are identical or different and represent heterocycles, C1-C30 alcohols, poyletherols, polyesterols, amines, polyetheramines, polyesteramines, thioalcohols, polyetherthiols, polyesterthiols independently of each other; R1, R2 are identical or different and represent (A) independently of each other; and n represents a whole number ranging from 2 to 100; wherein A1, A2, B1 and B2 can each be substituted with C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkinyl, C1-C20 alkoxy, carbonyl oxygen (=O), or halogen at any position with the proviso that at least one substituent of B1 or B2 is a heterocyclic end group. The invention further relates to methods for stabilizing polymers against hydrolysis using oligomeric carbodiimides.