Conjunctival malignant melanoma (CMM) is a potentially lethal neoplasm with a high rate of recurrence. The modality of treatment includes a wide surgical excision, cryotherapy, topical mitomycin C and Interferon alpha 2b (INF α 2b). The aim of the study is to present the treatment of a case with CMM using topical Interferon alpha 2a. We present a 38-year-old female with diffuse bulbar dark pigmentation of the conjunctiva that arises from previously primary acquired melanosis (PAM). Biopsy resulted positive for CMM and further investigations were negative for any metastasis. Treatment with topical interferon alpha 2a was started immediately and after three months melanoma disappeared. One year after follow-up there was no sign of recurrence in regional lymph nodes or distant metastasis.