The purpose of this study was to determine the possible role of nasal septal deviation on volume of maxillary and frontal sinuses. Between February 2011 and October 2013, paranasal sinus computed tomography (CT) findings of 732 patients (410 males, 322 females) who were admitted to Ear Nose and Throat Department of Kayseri Research and Training Hospital were retrospectively analyzed. By excluding the other coexistent sinonasal pathologies, 83 consecutive patients with nasal septal deviations were included in the study. The volume of each maxillary and frontal sinus (ipsi- and contralateral to the deviation side) was also calculated using the computer program. There was no statistically significant difference between ipsilateral and contralateral maxillary sinus volumes in group 1 and group 3 (P > 0.05). There was a statistically significant difference between ipsilateral and contralateral maxillary sinus volumes in group 2 (P < 0.05). There was no statistically significant difference between ipsilateral and contralateral frontal sinus volumes in group 1, group 2, and group 3 (P > 0.05). Moderate septal deviation significantly affects the volume of maxillary sinus. Mild and severe septal deviation does not significantly affect the volume of maxillary sinus. Effect of septal deviation on frontal sinus volume was not detected. The probability to encounter maxillary and frontal sinusitis ipsilateral to the all septum deviation groups was significantly increased in both right- and left-sided subjects.