The risk for rupture of an abdominal aortic aneurysm is widely believed to be related to its maximum diameter. Rupture occurs at the site of maximum wall stress, when it exceeds the tensile strength of the aortic wall. Basic research confirmed that peak wall stress and aortic wall biodegradation contribute to the mechanism of aneurysm rupture. In order to highlight the role of loss in wall strength and increase in focal peak stress, the authors reviewed recent literature. The clinical relevance of these recent insights in the etiopathogenesis of aneurysm rupture is analysed.