The purpose of the paper is to introduce a new failure rate-based methodology for reliability simulation of deep submicron CMOS integrated circuits. Firstly, two of the state-of-the-art MOSFET degradation models are reviewed. They have been developed into reliability simulation tools and commercialized in industry for many years, however, their inherent limitations of characterizing circuit lifetime, including tedious processes for extracting device degradation parameters and model fitting parameters, impeded their wide applications in the product's front-end design process. Secondly, a set of accelerated lifetime models for the most important intrinsic silicon degradation mechanisms are proposed. These lifetime models correlate a device's electrical operating parameters to its mean time to failure (MTTF) in simple forms. Finally, a new failure rate-based SPICE reliability simulation methodology is developed, in which MTTF and failure in time (FIT) are the primary reliability parameters to be characterized. The power of this new reliability simulation method, due to its simplicity, makes it an important design-for-reliability tool for electronic product developers.