AbstractWe describe the cytomorphology of seven cases of metaplastic carcinoma of the breast studied by fine‐needle aspiration cytology and by histology. All seven cases contained foci of ductual adenocarcinoma. This finding was combined with heterologous mesenchymal elements in four cases, a spindlecell pattern of growth in one case, and extensive squamous‐cell metaplasia in two cases. Both carcinomatous and metaplastic components were present on smears in four cases (57%). Thus in three cases (43%), the diagnosis was not possible on smear material alone. Differential diagnostic considerations are discus