Background: The clinical symptoms and treatment outcomes of chronic sinusitis are influenced by environmental factors, limited access to health care services, and it is a significant health burden in Iraq. The main goal of this research was to assess the efficacy of FESS and assistive procedures in the nose. A prospective observational study was performed from January 2025 to January 2026, in two specialized ENT centers in Iraq, where 134 patients with drug-resistant chronic sinusitis were included. Our primary outcome measures included the SNOT-22 score, the nasal obstruction/ facial pain/ smell (visual symmetry) scores, and the NOSE score. · Significant improvement was observed in all outcome measures after 12 months, the SNOT-22 from 52.4±18.7 to 18.8±10.6 · The NOSE score from 72.8±16.4 to 20.2±11.6 · The peak inspiratory nasal airflow increased from 78.4±28.6 to 132.8±31.2 L/min · Surgical success, overall, did not change after 12 months (82.1%). In summary, in Iraqi people with treatment-resistant chronic sinusitis, high BMI, and EDSS are independent predictors of decreased likelihood of success.