The application of rubber seed oil (RSO) and epoxidized RSO (ERSO) as a plasticizer in acrylonitrile butadiene rubber (NBR) was studied using RSO and ERSO with different levels of epoxidation. The results indicated that ERSO could be used as a less leachable and low volatility plasticizer for NBR. The use of ERSO in NBR gave better abrasion resistance whereas the tensile strength and tear strength were comparable to those vulcanizates that contained dioctyl phthalate as a plasticizer. (C) 2003 Wiley Periodicals, Inc.