Styrene-butadiene rubber (SBR), polydimethyl siloxane rubber (MQ) and their blends cure with sulphur, peroxide and combinations of both systems, Cure characteristics and vulcanizate properties are compared, The best results are obtained with SBR/MQ = 80/20 blends, For determining (M) over bar(c) and crosslink density v, stress-strain measurements, Mooney-Rivlin parameters and new equations are used. They are in good agreement with the already known and recognized equations. Some torn vulcanizate surfaces of such blends were studied by SEM.