This paper presents the establishment of an equation fitting the evolution of the self-heating of a polychloroprene rubber during uniaxial fatigue tests. A wide range of loadings was investigated in order to cover low and high cycle fatigue behavior for several load ratios taken between -0.3 and 0.5. The study consists in firstly measuring the evolution of the self-heating during a fatigue test. Then, after computing the derivative, the resulting curve is fit with an equation composed of three components: two of the form of a negative exponential and a constant. It is then integrated to obtain an equation that would fit the evolution of the self-heating for all the loadings investigated. It is observed that the parameters are correlated with the intensity of the stress and the load ratio applied during the test. Consequently, it is proposed that one of the parameter is linked to the viscosity, the parameter linked to the first negative exponential is related with the viscosity, the parameter linked to the second negative experimental is related to the damage induced by the low cycle fatigue loading and the parameter integrated from the constant is related to the influence of the presence of a sizable crack on the temperature field.