Introduction: Disorders of the nose and paranasal sinuses are among the most common chronic illnesses. Although considerable progress has been made in the medical and surgical control of these diseases, a large number of questions relating to the diagnosis, evaluation, and treatment of these conditions remain unanswered. The aim of the present study was to evaluate differences in the frequency of symptoms and disease severity in patients with nasal septal deviation (NSD) compared with chronic rhinosinusitis (CRS). Materials and Methods: A total of 156 patients, divided into NSD and CRS groups, were studied in relation to symptoms and disease severity. Patients were selected from those referred to the Ear, Nose, and Throat (ENT) Wards of the Imam Reza and Ghaem Hospitals, who had not responded to a variety of treatments. Depending on the type of disease, patients were candidates for either septoplasty or endoscopic sinus surgery. The Rhinosinusitis Symptom Inventory was administered to measure the severity of symptoms, with scores assigned based on the answers given by patients (Likert scale). Scores were compared between the CRS and NSD groups. Results: A total of 156 patients (78 with NDS and 78 with CRS) entered the study in overall sinonasal symptoms were more prevalent in CRS group. Nasal congestion, runny nose, earache, toothache, and smelling disorder were significantly more common in the CRS group (P<0.001); while there were no significant differences in symptoms such as facial pressure, fever, or headache between the two groups (P>0.05). Conclusion: Patients with CRS manifested statistically significantly greater sinonasal symptom scores than patients with NSD. [ABSTRACT FROM AUTHOR]