OBJECTIVE To evaluate the relationship between the degree of nasal septum deviation and inferior turbinate hypertrophy with the CT. METHODS The paranasal sinus CTs of 98 cases with septum deviation were evaluated. Inferior turbinate on the deviated side of the nasal septum was considered as the control group and the inferior turbinate on the other side was taken as the study group in the same patient. The septal deviation angle, thickness of the bone, medial mucosa and lateral mucosa of the inferior turbinate were measured. RESULTS The thickness of the bone, medial mucosa and lateral mucosa of the inferior turbinate were statistically different between the study group and the control group(P<0.05). There were statistically differences between the medial and lateral mucosal thickness in study group(P<0.05). There was no positive correlation between the deviation angle and the thickness bone, medial and lateral mucosa of the inferior turbinate in the study group(P>0.05), but the value of correlation coefficents revealed the inferior turbinate bone correlated with the deviation angle most, followed by medial and lateral mucosal thickness. CONCLUSION The hypertrophy of inferior turbinate in patients with nasal septum deviation is not only caused by mucosal hypertrophy, but also by hypertrophy of the inferior turbinate bone. The preoperative CT before septoplasty can be helpful to choose the surgical methods during the operation.