In an attempt to understand the effect of mode-mixity on the growth of a nominal defect under repetitive sub-critical loads, fatigue experiments are conducted on an Aluminium alloy at different mode-mixities. Three-dimensional finite element simulations akin to experiments are performed at different crack lengths and mode-mixities to study their effect on the opening stress, stress-state characterised by triaxiality parameter and equivalent plastic strain, at the mid-section of the model specimen. © 2014 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.