The bromination of diacetals of terephthalaldehyde and glutaraldehyde by means of polymeric brominating reagents (PBR), poly(N-bromoacrylamide), copoly(N-bromomaleimide(arnide)-limonene and poly(N-bromomethacrylamide) Amberlite IRC-50 Br, was described. The bromination by PBR is more specific than that by 1,3-dibromo-5,5-dimethylhydantoin (DBDMH). The reactivity of -NHBr groups in the oxidation of acetals is considerably influenced by -COOH groups present in the backbone of PBR.