A method for utilizing waste cement dusts as fillers for styrene-butadiene rubber (SBR) is presented. Such fillers were introduced into the elastomer system together with the waste silica (post-HF silica). The surfaces of both fillers were modified using proadhesion compounds (silane and titanate coupling agents). The modified fillers evidently increased strength parameters of the studied vulcanizates. This was attributed to the hydrophobization of their surfaces and to the introduction to the surfaces of functional groups with chemical affinity to the polymer.