Malignant ectomesenchymomas, rare and potentially aggressive tumors, occur in children and exhibit mesenchymal and neuroectodermal components. This report describes the first patient diagnosed with a malignant ectomesenchymoma of the hand. The patient was a 17-month-old male who developed a hypothenar mass on his left hand that was surgically excised. Microscopic evaluation revealed ganglioneuroblastic, rhabdomyosarcomatous, and chondrosarcomatous elements. Following excisional biopsy he was treated with cyclophosphamide, doxorubicin, vincristine, ifosfamide, and etoposide. After 3 courses of chemotherapy the patient had a wide reexcision with no residual tumor. The patient is 4 years from diagnosis, without evidence of disease.