Rolling contact fatigue (RCF) corresponds to the formation of the first spall, which is a stochastic behavior; therefore, the RCF life should be reliably calculated. A method for evaluating RCF reliability was developed based on the Lundberg-Palmgren theory and ISO 281. The method took into consideration the contact load, the geometric parameters of contact pairs, the oscillation amplitude, the RCF reliability and the material properties. Because the method was derived from a widely accepted theory and empirical standards, it can be used for engineering applications. Finally, the RCF reliability of a slewing bearing under complex operating conditions was determined using the developed method.