Background Wegener granulomatosis (WG) is an uncommon systemic necrotizing vasculitis that demonstrates renal and respiratory tropism. While the pathogenesis of WG remains controversial, autoimmune and inflammatory mechanisms are likely to be involved. The nervous system could be affected in up to 54% of cases. Although central nervous system involvement has been reported in 7–11% of cases, aneurysmal subarachnoid hemorrhage (SAH) occurrence is exceptional. Methods We describe the third reported case of WG-related aneurysmal SAH and then discuss the diagnosis and pathogenesis of WG along with the physiopathology of intracranial aneurysm in light of recent data reported in the literature. Results A 63-year-old woman with WG was referred to our neurosurgical department for aneurysmal SAH. The vasculitis diagnosis had been established 4 years earlier when she presented with chronic sinusitis, recurrent cystitis, and renal failure. The cerebral angiography revealed an anterior communicating artery dysplastic aneurysm. The neurosurgical management of the aneurysm was scheduled but delayed because the patient was experiencing a vasculitis flare-up. Immunosuppressive therapy and intravenous corticotherapy were given, with the patient's improvement, allowing neurosurgical clipping of the aneurysm. Conclusions Wegener granulomatosis-related aneurysmal SAH is an exceptional condition in neurovascular pathology. As inflammatory mechanisms are involved in the pathogenesis of aneurysm, the vasculitis flare-up could account for this SAH. The management of WG could benefit from anti-inflammatory therapy, as could the vasculitis-related SAH. SAH occurrence in patients with systemic vasculitis could indicate a vasculitis flare-up.