Acute invasive fungal rhinosinusitis occurs almost exclusively in patients with immunodeficiency, particularly cellular immunodeficiency. AIFRS rapidly spreads through nasal mucosa and sinus to the orbit and brain. Necrosis and vascular invasion are characteristics of AIFRS. Diagnosis is made by biopsy and obvious fungal invasion associated with necrosis in the nasal mucosa and underlying bone. High mortality rate has been reported in these patients (50-80%). This case study reviewed patients treated for AIFRS in 2012 to 2014. Diagnosis was based on clinical course of acute disease (less than 4 weeks) and fungal invasion confirmed by the pathology. Among 41 patients with AIFRS, fever was the most common initial manifestation (n = 33, 80.5%). Involvement of orbit (100% vs. 18.2%, p<0.001,) skull base (100%, p=0.001) palate and nasal floor (83.3% vs. 15.2%, p=0002) and lateral nasal wall (50.0% vs. 6.1%, p=0.019) was significantly higher in died patients than the improved patients. Recovery was reported in 80% of patients receiving endoscopic and pharmaceutical treatment. Early treatment of patients with sinus mucormycosis using endoscopic surgery improves overall survival. Poor prognosis was associated with extranasal involvement such as orbit and central nervous system (CNS) involvement.