Although rare, malignant melanoma occurs in children. The risk of degeneration of a congenital melanocytic nevus into a melanoma is approximately 0.7%. We report a case of malignant melanoma that developed on a congenital melanocytic nevus in a 19-month-old boy. The child was treated by surgical resection, superficial parotidectomy, and modified radical neck dissection with adjuvant therapy. The follow-up has been 24 months without metastasis. Early clinical detection, fast histological confirmation, prompt surgery, and adjuvant therapy are the only means to achieve a long survival period for children suffering from malignant melanoma.