Dye testing with a nasal speculum and nasopharyngoscope was performed in 45 consecutive cases after dacryocystorhinostomy. Testing was positive in 60% of cases with a patent dacryocystorhinostomy when the nasal speculum alone was used to examine the nose. When the nasopharyngoscope was used, however, dye testing was positive in 98% of cases. In 2% of cases with a functioning dacryocystorhinostomy, the dye test was negative and the nasal ostium could not be visualized. The nasal ostium could not be visualized in 16% of cases because of severe nasal septal deviation or other nasal anatomic change. It is concluded that dye testing is a reliable measure of lacrimal drainage function after dacryocystorhinostomy when nasal endoscopy is performed and when the nasal ostium and surrounding nasal mucosa can be visualized.