AIM: To report symptoms and findings of lacrimal duct malfunction after topical mitomycin C (MMC) for conjunctival neoplasia. METHODS: 14 consecutive patients treated with 1-6 cycles of topical 0.04% MMC four times daily for periods of 2 weeks were interviewed about symptoms of lacrimal duct malfunction. Patients who complained of tearing had examination of the puncta and canaliculi including probing and lacrimal duct irrigation. RESULTS: Nine patients complained of epiphora after topical MMC. Three of these patients had normal puncta and canaliculi, patent to irrigation. In these patients epiphora ceased spontaneously after probing and irrigation. The additional six patients had stenosis of the punctum (n = 3), the common canaliculus (n = 1), both puncta and both canaliculi (n = 1) and complete occlusion of the lower canaliculus (n = 1). CONCLUSION: Obstruction of the puncta or canaliculi is not an infrequent event after topical 0.04% MMC.