Background: olfactory dysfunctions affect daily life activities. Nasal surgeries primarily aims at elimination of nasal obstruction and removal of nasal polyps or inflamed mucosa. Improved olfactory function after these surgeries may be a secondary benefit. Objectives: this study aimed to evaluate different types of smell dysfunctions before and after different nasal surgeries and its liability to improve or not after surgery and to discuss CT scan results in these cases in correlation to clinical and surgical results. Study Design: prospective study. Methods: a total of 50 patients were included in this prospective study (32 men, 18 women; age range was 20–49 years, mean age 32 years, standard deviation =7.3years). Patients were suffered from different nasal diseases requiring surgical interference and complaining of smell dysfunctions as one of the main nasal symptoms. Patients were selected from those attending E.N.T Clinic in Bab EL-Sharia Hospital, Faculty of Medicine, Al-Azhar University from February 2017 to April 2018. Prior to surgery, patients received a detailed otorhinolaryngologic examination included nasal endoscopy. Olfactory function was evaluated subjectively. CT scan nose and paranasal sinuses (coronal and axial) was done before the surgical interference and repeated after complete healing of the operation. Questionnaire was directed to each patient to tell which type of smell dysfunctions he was complaining of and the severity of this dysfunction, this questionnaire was repeated after the complete post-operative period. The patients were followed up after the operation in scheduled sessions for five months. Results: after different nasal surgeries no change of olfactory dysfunction was found in 26% and improvement was seen in 74%. As regard patients underwent endoscopic sinus surgery no change of olfactory dysfunction was found in 32% and improvement was seen in 68%; however in the septoplasty group no change of olfactory dysfunction was found in 50% and improvement was seen in 50% and in septoplasty and inferior turbinectomy group, no change of olfactory dysfunction was found in 14.3% and improvement was seen in 85.7%. in patients who had hyposmia no change of olfactory dysfunction was found in 17.9% and improvement was seen in 82.1%, whereas in patients who had anosmia, no change of olfactory dysfunction was found in 42.9% and improvement was seen in 57.1%; patients who had cacosmia, no change of olfactory dysfunction was found in 14.3% and improvement was seen in 85.7%. Free postoperative CT was found in 92% and recurrence was seen in 8%. Conclusion: the different nasal surgeries showed significant effect on olfactory function in Patients with subjective olfactory dysfunction. However, considerable number of patients with olfactory dysfunctions did not improve after surgery. CT scan is useful in the assessment of patients with olfactory dysfunction associated with many sinonasal diseases.