This article reports the clinical, histopathologic, and immunohistochemical findings in a case of small cell undifferentiated carcinoma of the submandibular gland. The tumor was composed of anaplastic cells slightly larger than lymphocytes without ductal differentiation. On immunohistochemical analysis, the tumor contained cells that reacted positively with antibodies to cytokeratin, neuron-specific enolase, synaptophysin, and chromogranin. The present case supports the hypothesis that small cell undifferentiated carcinomas of the salivary glands arise from presumed multipotential ductal stem cells. When this tumor entity is located on the salivary glands, it appears to behave less aggressively than when it is a primary tumor of the bronchial tree.