PURPOSE: To report the efficacy of cimetidine for treatment of conjunctival papillomatosis. METHODS: An 11-year-old boy had an 8-year history of diffuse conjunctival papillomas, treated previously with standard measures of excisional biopsy and cryotherapy. He developed spontaneous conjunctival bleeding and diffuse tumor recurrence over the entire conjunctival surface. Oral cimetidine liquid (30 mg/kg/day) was prescribed. RESULTS: Within 2 months, dramatic tumor regression was noted, with nearly complete resolution by 4 months. The patient had no local or systemic side effects from the medication. CONCLUSIONS: Oral cimetidine possesses immune modulation properties and may be useful in some cases of virus-induced conjunctival papillomatosis.