ABSTRACTNitrile‐butadiene rubber (NBR) compounds were prepared with different amounts of hydrogenated transgenic soybean oil (HTSO) as renewable plasticizers. For comparison, similar compounds were prepared with petroleum‐based dioctyl‐phthalate (DOP), one of the most common plasticizers for NBR. Four HTSOs with different degree of hydrogenation were used, of which three HTSOs are prepared by hydrogenation reaction at different reaction conditions and one is commercial available. The plasticization effects of HTSO and of DOP were studied by Mooney viscometry, capillary rheometry, differential scanning calorimetry (DSC), and rubber processing analysis (RPA). The results showed that all the HTSOs had better plasticization effect than DOP on NBR. The swelling index result showed that the highly‐hydrogenated‐HTSO plasticized NBR vulcanizate have higher crosslinking density than the low‐hydrogenated ones. It is worthy to mention that, the introduction of high‐hydrogenated‐HTSO greatly improved both the processability of the NBR compounds and the mechanical performance of the final products, which is hard to achieve for most of the plasticizers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40643.