An adduct of hexamethylene isocyanurate and isopropylidene malonate was prepared and tested as a crosslinker in a one-pack water-borne polyurethane system. It was characterized by FTIR, NMR, and SEC; the blocking and curing courses were followed by FTIR and DSC. The crosslinker was a mixture of various oligomers having mainly amide-type linkages. The cure analysis showed that cleavage of the malonate ring started at around 110 degrees C and was followed by the formation of ester-type products. After 30 min of heating at 130 degrees C the insoluble part of crosslinked polyurethane films exceeded 80%.