True mycotic aneurysms are extremely rare cerebrovascular lesions with a dismal prognosis. They mostly follow fungal meningitis or septicaemia and herald their presence with the development of subarachnoid haemorrhage. The authors report an extremely rare occurrence of bilateral anterior cerebral artery aneurysms caused by mucormycosis. The infection was diagnosed after investigation of prolonged fever following transsphenoidal surgery. The aneurysm was diagnosed after a subarachnoid haemorrhage and the patient finally died. The present case highlights an atypical presentation of fungal infection that can perplex the best of clinicians and thus delay diagnosis. As subarachnoid haemorrhage due to true mycotic aneurysmal rupture is uniformly associated with a fatal outcome, the authors speculate that a high index of suspicion should be maintained when a neurosurgical patient is predisposed to fungal infection. This approach, combined with the empirical institution of antifungal drugs, provides the only chance of survival.