This article examines all cases of malignant melanoma referred to Children's Hospital, Boston, and to the author over the period 1959-1995. Criteria for inclusion in the study included (1) age up to 15 years, (2) availability of microscopic slides, and (3) availability of demographic data. There were 11 boys and 12 girls, ranging in age from 2 to 15 (mean age, 9.4) years. Histopathologically the 23 tumors were categorized into four subgroups: (1) small cell melanoma (five cases), (2) adultlike melanoma (six cases), (3) Spitz-like melanoma (three cases), and (4) atypical Spitz tumors (nine cases). The small cell melanomas were notable for localization to the scalp, significant thickness, and fatal outcome. The adultlike melanomas resembled typical tumors occurring in adults. The one fatal Spitz-like melanoma was located on the neck of a 14-year-old boy. Two tumors in this group metastasized to regional lymph nodes but have not been associated with further aggressive disease on follow-up despite having been treated with surgical excision only. The atypical Spitz tumors were characterized by significant thickness and abnormal features, including prominent cellularity and mitotic activity. Anatomic site and cell type may be important prognostic factors in addition to tumor thickness in childhood melanoma but require further study. The biological potential of atypical Spitz tumors has not been sufficiently characterized.