The strain-life approach is the preferred approach for uniaxial and biaxial loading conditions and is particularly useful in situations with significant plastic deformation. This approach is used for materials where a fatigue curve is not provided in a governing code of construction standard. This article serves as an introduction to the strain-life approach to fatigue. The strain-life equation is derived, mean stress and biaxial loading are addressed, sources for parameters are listed, the Uniform Material Law is introduced, and an algorithm for determining life based on stress is presented.