Apocrine carcinoma is a rare form of breast malignancy and is composed of entirely or predominantly of apocrine type epithelial cells. Apocrine metaplastic cells are frequently noted in fine needle aspiration cytology(FNAC) of breast lesions, especially fibrocystic disease. These apocrine cells may occasionally be atypical, to make a diagnostic difficulty. Two cases of apocrine carcinoma of the breast diagnosed by FNAC are described, and differential cytologic points between apocrine metaplasia and apocrine carcinoma are discussed. The first case is a right breast mass of a 37-year-old woman for 20 days. The smears show many single or sheets of large cells on bloody background. Each cell has a large vesicular nuclei with multiple macronucleoli and abundant eosinophilic granular cytoplasm. The second case is a left breast mass of a 35-year-old woman for one month. The smears show similar findings as seen in the first one. Histopathologic findings of both cases are typical of apocrine carcinoma. Electron microscopy demonstrates variable numbers of large osmiophilic granules in diameter of $200sim600nm$ in both cases.