Blends of butadiene-acrylonitrile-rubber (NBR) and vinyl chloride/vinyl acetate copolymer (PVC/PVAc) were prepared in various ratios. The viscosity measurements and scanning electron microscopy revealed that NBR and PVC/PVAc copolymers are compatible in all ratios. Comparative studies of the curing characteristics of such blends as well as physico-mechanical properties, swelling behaviour and dielectric measurements of their vulcanizates were investigated. The test cure system ethylene thiourea/sulphur (ETU/S) and the conventional cure system cyclohexyl benzothiazole sulphenamide/tetramethylthiuram disulphide/sulphur (CBS/TMTD/S), both produce crosslinking effects which are comparable to each other; particularly with respect to physico-mechanical properties of the blend vulcanizates and their degree of swelling in motor oil. Also, the dielectric measurements taken for the(.) blend vulcanizates containing various white fillers indicate a substantial decrease in the dielectric constant (epsilon') and the dielectric loss (epsilon ").