This invention relates to elastomeric compositions comprising at least one polymeric elastomer, at least one propylene polymer, and at least one curing agent. The elastomer compositions can optionally contain other rubbers, such as natural rubber and a variety of other ingredients. The compositions containing propylene polymers and copolymers can have better processability and lower compound viscosities and can show an improvement in at least one of the following properties: air permeability, tensile strength, elongation, tear strength, adhesion, dynamic performance, flex fatigue resistance, and cure characteristics. These elastomer compositions are believed to be useful for applications where elastomeric polymer is currently used, such as, tire inner liners for tubeless tires, tire inner tubes, and ball bladders to name a few.