The aim of this study was to report on the effectiveness and tumor side effects of topical interferon (INF) alpha 2-beta in a case of conjunctiva-cornea intraepithelial neoplasia (CIN) of a patient that rejected any surgical procedure. This study is a case report description. An 81-year-old man with a history of neoplasies of the colon and prostate and anticoagulant treatment was referred for treatment of an ocular surface neoplasia on his left eye. Pathognomonic signs of CIN were present. The patient rejected surgical procedures. A regimen of topical INF alpha 2-beta 4 times daily was administered. An increase in tumor volume of 25% was observable 15 days after the beginning of therapy. No subjective discomfort was reported. The treatment continued with follow-ups every 15 days. The progressive regression was remarkable. Complete regression of the CIN was observable after 60 days of therapy. No other side-effects were detected. Topical INF alpha 2-beta is a valid choice for the treatment of CIN in patients for whom surgery is not possible. The increase of tumor volume at the beginning of therapy does not require the suspension of treatment.