Background: The maxillary sinus is the most one vulnerable to lesions. It has a great variation in size, shape, position, and pneumatization, not only in different persons, but also in different sides of the same person. Objective: The aim of this study was to define the pneumatization pattern of the maxillary sinus prelacrimal recessand its impact on endoscopic access. Patients and methods: A series of 99 paranasal CT scans were analyzed retrospectively to define the pattern of pneumatization of the maxillary sinus prelacrimal recess. In a total of 198 maxillary sinus, the distance between the maxillary sinus anterior wall and the anterior margin of the nasolacrimal duct were measured in a millimeter (mm). Results: A total of 99 patients, 54 (55%) were males and 45 (45%) were females with age ranged from 18 – 69 years, with 198 maxillary sinus prelacrimal recess were measured. There are 3 types of pneumatization: Type I (0–3 mm), Type II (> 3–7 mm) and Type III (> 7 mm). In our study we found that type III was found in 24 maxillary sinus (12 %), type II was present in 156 maxillary sinus (79 %) and type I was present in only 18 maxillary sinus (9 %). Conclusion: In 12 % of maxillary sinuses there was a widely pneumatized prelacrimal recess, which allow easy endoscopic access, while in 79 % there was a narrow recess so, temporary lacrimal duct dislocation is required to allow endoscopic access and in 9 % there was a very narrow recess so, lacrimal duct dislocation is always needed with bone removal to enable endoscopic access.