Objective: To describe the clinicopathological characteristics of transitional cell carcinoma of the lacrimal sac. Methods: The patient underwent eye, ear, nose, throat, and systemic clinical examination. Ancillary tests including skull x-ray, computerized tomography (CT), and histopathologic examination of the lacrimal sac biopsy were performed. Exenteration and adjunctive radiotherapy were the treatments of choice. Results: A 58-year-old man had right proptosis due to a mass affecting his right lacrimal sac, orbit, ethmoid sinuses, and nasal cavity. Light microscopy and immunohistochemistry diagnosed transitional cell carcinoma of the lacrimal sac. Conclusion: Clinically and histopathologically, our case of transitional cell carcinoma of the lacrimal sac had a poor prognosis due to the resected tumor's surgical borders involvement upon histopathologic examination, as well as local invasion.