This paper explains the problems with the Mil-Hdbk-217, "Reliability Prediction of Electronic Equipment," approach to assessing the reliability of electronic packages and summarizes the current activities of the US Army in the transition toward a more scientific, physics-of-failure based approach. The paper compares these two approaches, and notes the problems with using statistical field-failure models for the design, manufacture, and support of electronic equipment. The US Army began transition from Mil-Hdbk-217 to a more scientific, physics-of -failure approach to electronic equipment reliability. To facilitate the transition, IEEE reliability Program Standard is under development to incorporate physics-of-failure concepts in to reliability programs. Software tools are also being developed to assess the reliability of microelectronic packages and circuit card assemblies. Various US Army physics-of-failure reliability assessment projects have either been completed, or are currently being performed. The importance of these projects in effecting the transition to physics-of-failure based models is highlighted.