Abstract Addition of cryoground rubber (CGR) causes changes in curing characteristics (decrease in Mooney scorch time, optimum cure time, and reversion time) and shows a detrimental effect on most of the vulcanizate properties (tensile, resilience, flex, hysteresis, set, and abrasion). Tear strength, however, is not adversely affected by CGR. Higher doses of curatives (sulfur 3.5 phr and acelerator 1.4 phr) and addition of reinforcing carbon black make up the losses in physical properties. Scanning electron microscope fractographs show that there is little adhesion between natural rubber and CGR. But addition of carbon black overshadows the effect of CGR, and the fractographs show the characteristics of black-filled vulcanizates.