A 65-year-old woman was diagnosed clinically to have a tarsal conjunctival malignant melanoma of the upper eyelid. She also had multiple, diffusely pigmented, flat conjunctival lesions. No local or distant metastasis was detected. She was treated conservatively by a combination of surgery and cryotherapy as this was her only seeing eye. Histopathology of the tumor tissue and biopsy specimens of the flat conjunctival lesions proved them to be conjunctival malignant melanoma and primary atypical melanosis with atypia, respectively. Over a follow-up of two years, no clinical recurrence of the tumor was seen. To conclude, a malignant melanoma arising from the tarsal conjunctiva is extremely rare. The goal of treatment should be eradication of the tumor as well as preservation of a functionally and cosmetically acceptable eye.