Secretory carcinoma is a very rare tumor of the breast, having characteristic histologic findings. A cytologic study of a secretory carcinoma is presented. The smears were abundant in tumor cells which were arranged in loosely adherent or large tight clusters in clear background. The individual cells were round or oval, monomorphic, and had abundant eosinophilic cytoplasm. The cytoplasm showed distinct borders and single or fine vacuolization. The nuclei were peripherally located, oval, and vesicular with small prominent nucleoli. As in histology, the cytologic features were so characteristic that a diagnosis of secretory carcinoma could be made by ctyologic study only.