Four cases of malignant melanoma in children younger than 17 years of age are presented. Several preexisting conditions increase the risk of development of melanoma during childhood. These include giant congenital melanocytic nevi, the familial dysplastic nevus syndrome, and xeroderma pigmentosum. The role of small congenital lesions and sporadic dysplastic nevi in the development of melanoma in children is less clear. The signs and symptoms associated with melanoma in children are similar to those in adults, as are the histopathologic features, biologic behavior, and treatment of this tumor. The inadequacy of available therapy for metastatic melanoma underscores the necessity for the early diagnosis and prompt surgical treatment of melanomas in children.