BACKGROUND : Invasive sinonasal aspergillosis is rarely seen in immunocompetent individuals. It may involve adjacent intracranial and intraorbital structures causing high morbidity and mortality. METHODS : We report a rare case of invasive Aspergillus sinusitis in a young, immunocompetent woman causing headache and vision loss. Endoscopic débridement under general anesthesia was complicated by rupture of a mycotic cavernous carotid artery aneurysm. This was managed by packing with muscle and fascia followed by endovascular coiling. Subsequently, the aneurysm extended intradurally and caused fatal subarachnoid hemorrhage. CONCLUSIONS : This case emphasizes the need for early diagnosis of invasive fungal sinusitis to prevent intracranial complications and fatal outcome. When the diagnosis is made, aggressive treatment with surgical débridement and adjuvant antifungal therapy is required. Internal carotid artery involvement is a rare but life-threatening complication of invasive fungal sinusitis.