The surgical complication rates during FESS may be reduced by knowing the anatomic variances, which explains illness recurrence and allows for a modification in operating approach. Sinusitis and the spread of infection to nearby structures may have these variances as an etiological cause. Variations in the sinuses seen on a CT scan are the focus of this study, and the researchers are interested in learning more about them. Methods and patients: There were about 500 Egyptian patients who had regular MSCT of the paranasal sinuses from January 2019 to January 2020 who were included in this research. A thorough medical history, an ENT exam, and an MSCT of the paranasal sinuses were obtained for each participant (PNS). Results : The average age of the patients in the research was 29 years and 14 months. Males made up 45.8% of the patients, with females making up the remaining 50%. (54.2 percent ). Nasal obstruction (76.0 percent), discharge (61.6 percent), blurring of vision (25.0 percent), and dizziness were the other common symptoms (6.0 percent ). Agar nasi (86.4%), nasal septal deviation (76.2%), sphenoid sinus septation (74.2%), Maxillary sinus hyper-pneumatization (66.0%), Haller cell (65.8%) and Frontal sinus septation (65.8%) were the most common variants (60.2 percent ). Patients with sinusitis had substantially more agar nasi (95.3%) than those without (75.3%) (P 0.01). With sinusitis (93.5 percent), haller cells were substantially greater than those without (31.4%). (P 0.001). Conclusion: Paranasal sinus variations may be detected with MSCT, which is an essential part of preoperative evaluation. MSCT can also be used to identify anatomical abnormalities and their link to sinusitis.