This article is one case report of 49 year-old woman diagnosed with malignant melanoma of the anal canal. The tumor was detected at early stage and initially treated with local excision, followed by adjuvant interstitial brachytherapy. Since the patient complained of painful local ulceration and atypical cells were found at biopsy, abdominoperineal resection of the rectum was performed and a sterile specimen was obtained, proving the efficacy of adjuvant brachytherapy for local control. Patient is now considered disease free for 30 months after primary treatment.