Awad OGAN, et al. - In this prospective cross-sectional study, the researcher examined the difference between exclusive tobacco cigarettes smoking vs tobacco plus cannabis smoking regarding severity of chronic rhinosinusitis (CRS). Using SNOT-20 questionnaire, Lund-Mackay CT score and Lund-Kennedy (LK) endoscopy Score, CRS severity was evaluated and compared between two groups (Group 1: tobacco cigarettes smokers; 100 patients and group 2: tobacco cigarettes smokers and also cannabis users; 100 patients). Compared to patients who smoked tobacco cigarettes only, adult patients who smoked tobacco cigarettes plus cannabis mixed with tobacco had greater health-related quality of life burden and more severe CRS.