Objective:To investigate the clinic-cytology and histopathology of non-Hodgkin lymphoma (NHL) in breasts. Mothods:Twelve cases of NHL of the breast were studied by fine-needle aspiration biopsy (FNAC), histopathology and immunohistochemistry, and whose clinical data were analysed at the same time. Results:In 12 cases of NHL, 3 cases were T-cell NHL and 9 cases were B-cell NHL. Cytologically, the T-cell NHL cells were mostly arranging in diffuse patterns. The tumor cells were oval and pleomorphism. Some of them had distorted nucleus and thin nuclear envelope.The nucleus showed irregular course chromatin and visible nueleoic. Histopathologically, some of the tumor cells distributed around the blood vessels, and there was an obvious phenomenon of “blood-vessel-closing”. B-cell lymphoma cells were arranginy in diffuse pattern, and showed round and ellipse in shape with a clot and course granular chromatin and visible nueleoic and karyoknesis. Lymphoepithelia lesions were seen. Immunohistochemistry showed that CD3, CD43, and CD 45RO in T-cells NHL were positive.CD20, CD74 and CD79a in B-cells NHL were negative. CK, EMA, ER and PR in NHL were all negative. Conclusion:NHL of breast is extremely rare, and its definite diagnosis depends on various examination methods.