Choristomatous lacrimal gland tissue has been detected in many different sites of the ocular adnexa, but has never before been convincingly described in the submucosa of the lacrimal sac. A 77-year-old woman with epiphora had a biopsy of the sac wall preformed during a dacryocystorhinostomy that contained such a lacrimal choristoma. Zymogen granules were found in the cytoplasm of the secretory cells with the periodic acid-Schiff reaction. No mucus-producing cells, as found in normal sac submucosal glands, were detected using the Alcian blue, mucicarmine, and Gomori methenamine silver histochemical stains. Gross cystic fluid protein-15 positivity was demonstrated immunohistochemically. The clinical implications of this choristoma are explored.