Two rare cases of a tubular adenoma of the breast are reported, together with a clinicopathological review of the pertinent literature. Only 14 cases of this histological type have so far been reported in Japan. Both patients were single women aged 22 and 34 years, respectively. In case 1, a mass was found in the axilla, and in case 2, a breast cancer was simultaneously found in the contralateral breast. In each patient, a mass that measured 2 cm in diameter was oval, elastic and firm and smooth on the surface. In each instance the result of the biopsy performed led to a diagnosis of a fibroadenoma. Microscopically, the tumor was sharply demarcated from the adjacent breast tissue and consisted of homogeneous epithelial cells with small tubular structures and a minimal stromal component.