Intranasal endoscopic sinus surgery has several potential ocular complications, including visual loss, diplopia, retrobulbar hemorrhage, and epiphora. We treated eight patients with persistent nasolacrimal duct obstruction after endoscopic sinus surgery. All patients required dacryocystorhinostomy to achieve a patent lacrimal system drainage. To our knowledge, this is a previously unreported complication in the ophthalmologic literature. The relevant anatomy of the nasolacrimal duct is discussed in addition to surgical procedures for avoidance and treatment of iatrogenic injury to the system. Endoscopic sinus surgery is a highly successful procedure that is rapidly gaining popularity among otolaryngologists. As the number of patients undergoing this type of surgery increases, an increase in the relative number of ocular complications should be anticipated.