Background: Chronic dacryocystitis is the most frequent disorder in the lacrimal drainage system. The disease has been considered to be strongly associated with obstruction of the lacrimal duct, which creates a fertile environment for bacterial colonization and promotes lacrimal sac inflammation. Objective: The aim of this work was to evaluate lacrimal sac diameter in different age groups using ultrasound biomicroscopy (UBM). Patients and Methods: Twenty-four eyes of 24 normal individuals. They were divided according to age into 3 groups; group A: age ranging between 30 and 40 years, group B: age ranging between 40 and 50 years and group C: age above 50 years. Lacrimal sac diameter was assessed. Ocular examination and special tests were done for lacrimal drainage system (regurge test and fluorescein dye disappearance test) with imaging of lacrimal passages by ultrasound biomicroscopy. Results: All patients had no symptoms of epiphora, negative both regurge test and dye disappearance test and clear contents of the lacrimal sac. There was no statistically significant difference between groups regarding either longitudinal or horizontal lacrimal sac diameter. Conclusion: UBM can be used for imaging and measuring lacrimal passages and thus can be useful as an adjunctive to clinical examination and surgical planning in cases with lacrimal system diseases.