The development of hydrogenated nitrile-butadiene rubber (HNBR) was due to the necessity of elastomers to withstand higher operating temperatures. Certain market segments are closed to HNBR due to some limitation in low temperature flexibility as a result of its chemical structure. The solution, presented in this paper, is the development of a modified hydrogenated acrylonitrile (ACN)-butadiene (BD) copolymer. Optimization of the composition, the glass transition temperature (Tg) and oil resistance of the hydrogenated polymers can be achieved with the help of a computer program using the Alfrey-Goldfinger Gordon-Taylor, and solubility parameter equations. Modified copolymers have been prepared and hydrogenated. The hydrogenated polymers are characterized by conventional analytical techniques The test results confirm the theoretical predictions. The enhancement of the service temperature range for HNBR promises broad applicability in the automotive and industrial applications.