Adenomyoepithelioma (myoepithelioma) of the breast in a 47-year-old man is reported. The tumor consisted of a prominent proliferation of spindle cells surrounding mammary ducts. Immunohistochemical and electron microscopic observations confirmed the myoepithelial origin of these spindle cells. This is the first report of an adenomyoepithelioma of the breast that developed in a male.