Below the incipient characteristic tearing energy (T₀), cracks will not grow in rubber under fatigue loading. Hence, determination of the characteristic tearing energy T₀ is very important in the rubber industry. A rubber cutting experiment was conducted to determine the T₀, using the cutting method proposed originally by Lake and Yeoh. Then, a fatigue crack propagation experiment on a edge-notched pure shear specimen under variable amplitude loading was studied. A method to obtain the crack propagation rate da/dN from the relationship of the crack propagation length (Δa) with the number of cycles (N) is proposed. Finally, the T₀ obtained from the cutting method is compared with the value decided by the fatigue crack propagation experiment. The values of T₀ obtained from the two different methods are a little different.