Objective: Transnasal endoscopic surgical treatments of the maxillary sinus (MS) and nasolacrimal canal (NLC) pathologies are very common. A detailed understanding of the anatomy of this region preoperatively affects the chancesof surgical success. Advances in paranasal sinus computed tomography (PNSCT) have yielded a better understandingof the surgical anatomy.Material and Methods: The anatomical relationships between the medial and anterior walls of MS and NLC involving 81 patients (41 males and 41 females) were analyzed by means of PNSCT sections. The anatomical relationshipof NLC with the MS anterior wall was evaluated and classified into unified and separate types. The separate-type NLCwas further classified as protruding or nonprotruding according to the localization of the medial wall of the MS. Inaddition, the vertical height of the lower meatus and long and short diameters of the NLC were measured.Results: The unified type was detected in 54 (32.9%) patients out of the total MSs of 164 patients. The distancebetween the anterior walls of the MS and NLC was 3.50 mm in females and 3.95 mm in males; this did not significantlydiffer between the genders. Further, 26 MSs were of the protruding type. The vertical height of the lower meatus was10.75 mm in females and 12.15 mm in males. The long diameter of the NLC was 6.30 mm in women and 6.80 mm inmen. The short diameter of the NLC was 4.85 mm in women and 5.00 mm in men.Conclusion: The relationship between the NLC and MS shows anatomical variations. Understanding these variationsbefore surgery can increase the success rate of endoscopic surgical procedures directed toward the medial wall of MSs.