Allergic fungal rhinosinusitis is a non-invasive form of highly recurrent chronic rhinosinusitis. A probable correlation between fungal sinusitis, a disorder resulting from fungal infections of the sinuses that can worsen nasal symptoms and complicate treatment, and allergic rhinitis has been shown by recent investigations. The aim of this study is to estimate the prevalence of fungal sinusitis among allergic rhinitis patients. This cross-sectional study was conducted among 150 patients with chronic Allergic sinusitis who were attending the ENT, Outpatient Department at a Tertiary Care Hospital. All patients were subjected to an X-ray of the Paranasal sinuses followed by diagnostic nasal endoscopy, then a fungal smear and culture were done. Demographic details, Comorbidities, symptoms and DNE findings were collected and analysed using SPSS v.21. The prevalence of fungal sinusitis in cases of allergic rhinitis was 25.3%. fungal sinusitis was found to be more common among the patients with aged 45 years above and the patients with comorbidities. We found an Association between fungal sinusitis with comorbidities (0.001). Patients with allergic rhinitis are more likely to experience fungal sinusitis. For people with allergic rhinitis, a fungal sinusitis diagnosis and prompt treatment are essential to reducing symptoms and improving quality of life.