Golf balls golf balls containing a core having at least two layers made from a polyalkenamer rubber composition are provided. At least one layer is made from a relatively low modulus polyalkenamer rubber composition and at least one layer is made from a relatively high modulus polyalkenamer rubber composition. The rubber composition may further include other rubbers such as, for example, polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The rubber composition helps improve resiliency of the core. In one version, a dual-core having an inner core and surrounding outer core layer is provided. In another version, the golf ball contains a three-piece core having an intermediate core layer made of polybutadiene rubber.