Invasive fungal rhinosinusitis (IFRS) is a challenging condition and the mortality of IFRS in immuno compromised patients is very high. 75 patients of suspected FRS were included to study the burden and the clinicopathological and mycological profile of invasive fungal rhinosinusitis (FRS) in these patients. The samples collected were exudate from nasal debri, discharge and intraoperative tissue sample and were subjected to direct microscopy to histopathological examination and direct microscopy (KOH and calcofluor white) and culture on Sabouraud dextrose agar. Identification of molds and yeasts were done by conventional methods. 25 cases were suspected to have IFRS were confirmed by microbiological and histo pathological examination, comprising 56% of AIFRS (acute IFRS), 36% CIFRS (chronic IFRS) and 8% CGFRS (chronic granulomatous FRS). Rhizopus arrhizus (64.2%) was the most common isolate followed by Aspergillus flavus (35.7%). Mucor species were solely isolated from AIFRS (14.3%). In CIFRS, Aspergillus flavus (44.4%) seemed to be the major isolate with Aspergillus niger, Alternaria spp., Penicillium spp. and Candida albicans. Necrosis of submucosa, bone, vascular tissue was seen in 96% of cases with aseptate hyphae in 78.5% AIFRS and 77.7% in CIFRS. Radiological features help in presumptive diagnosis of FRS. Direct microscopy along with culture conformation is important for diagnosis and early initiation of treatment.