Predicting fatigue crack growth (FCG) rate and path under variable amplitude loading (VAL) is a crucial issue in damage tolerant design commonly used in aerospace industry. The aim of the current study is to predict FCG life under VAL through Extended Finite Element Method (XFEM) and to explicitly illustrate both FCG life and crack propagation. For this purpose an algorithm is developed and integrated in ABAQUS software to analyze 3D crack propagation under VAL using Modified Generalized Willenborg (MGW) retardation model. The results are compared with NASGRO crack propagation software and experimental FCG test data on 7075-T6 aluminum alloy under various over load (OL) and over load-under load (OL-UL) conditions which exhibit a good agreement. Copyright (C) 2016 The Authors. Published by Elsevier B.V.