Volumetric of air sinuses contributes in diagnosis of sinus pathologies, and applied in forensic field. The aim of the study was to estimate the volumes of paranasal sinuses in Saudi Arabia Qassim region relative to right, left, gender and age in normal patients. Methodology as retrospective study based on CT images for a sample size of 24 males, 26 females. The volumes derived from summation of areas of the sinuses and multiplying by the slice thickness in axial plane of CT image, which is, depend on 3D Slicer Program. The results showed that: the volume of the maxillary air sinus was the largest and the sphenoid and frontal air sinuses were the smallest, and the mean volumes of maxillary, ethmoid, frontal and sphenoid were 13.1,4.6,3.4 and 3.4 cm respectively. The maximum volumes of paranasal air sinuses occurred at 21-25 years old for maxillary and sphenoid air sinuses, while the maximum volumes for the ethmoid and frontal air sinuses occurred at 16-20 years old. The air sinuses have significant proportional correlation (R2 = 82) with aging. The data revealed that the growth rates of the two sides were symmetrical for all sinuses except for the frontal air sinuses. Male sinuses volumes were greater than female in different age groups for all sinuses.