['To present confirmed cases of type IIIb endoleak in second and third-generation stent-grafts used for endovascular aneurysm repair (EVAR).', 'Four patients developed type IIIb endoleak caused by fabric tears between 4 and 13 years following their initial EVAR. Three patients presented with rupture and one with aneurysm expansion of unknown cause. In each case, the type IIIb endoleak was confirmed at open surgery after imaging proved non-diagnostic. Only one patient survived. Had the cause for the expansion or ruptures been found prior to open reintervention, relining of the stent-graft may have been possible.'] Is type IIIb endoleak an important cause of failure following endovascular aneurysm repair?