This study aimed to describe the positions of the lamina papyracea (LP) in patients who had nasal polypi, by computed tomography (CT) analysis. Paranasal CT scans of patients diagnosed to have nasal polypi were included in the study. CT images were acquired with multiplanar reformates to obtain delicate details in coronal planes for all subjects. Positions of the LP were registered then analyzed in relation to nasal polypi grading. Forty seven subjects (94 nasal sides) were included in the current study. Grade I lamina detected in 50% or more of all cases. Patients who had larger polypi (polyp grade 3, 4) were associated with significantly more medial LP (grade II) than smaller polypi (polyp grade 0, 1, 2) (P=0.00386). The current study improves surgeons’ awareness of LP position in different grades of nasal polypi and highlights that larger polypi are significantly associated with more medial LP than smaller polypi. This may be one of the causes of the higher incidence of complication in larger polypi and can help for safer surgery.