This study examined the effect of cellulose nanocrystal (CNC) loading on curing characteristics and mechanical properties of acrylonitrile-butadiene rubber (NBR)/natural rubber (NR) nanocomposites. The blend ratio of NBR and NR was kept constant at 50/50, excluding the raw NBR (NBR100). Four distinct samples with different CNC loadings, in parts per hundred rubber (phr), including NBR-C0 (0 phr), NBR-C1 (1 phr), NBRC-3 (3 phr), and NBRC-5 (5 phr), were prepared using an internal mixer at 70 oC and a rotor speed of 15 rpm. The cure characteristics of the nanocomposites were studied using a moving die rheometer (MDR), while the mechanical properties of the vulcanizates were measured in accordance with ASTM standards. The results showed that scorch time, cure time and delta torque of rubber composites tended to increase with the CNC content, while NBR100 showed higher delta torque than those properties. Moreover, hardness, as well as the 100% and 300% modulus of rubber vulcanizates slightly increased with the CNC content. Furthermore, a NBR50-C1 composite containing CNCs at 1 phr showed an optimal value for tensile strength.