Isobutylene-Isoprene rubber (Butyl rubber) and butadiene acrylonitrile rubber (Nitrile rubber) blends were prepared by precuring the slower curing butyl rubber phase to a low level, blending it with NBR and then curing the blend. The mechanical properties of the blends prepared this way were compared with those of the conventional blends. The properties of the blends prepared by this novel method are much superior to those of the conventional blends. The novel blends exhibited superior tensile strength, elongation and tear strength. The improvement in tear strength was more pronounced in the case of blends containing medium nitrile NBR than those containing high nitrile NBR. Ageing resistance was also found better for the novel blends, being more significant in the blends containing medium nitrile NBR. The improved properties of the novel blends could be attributed to the better distribution of crosslinks in both the rubber phases.