Objective: To investigate the clinicopathologic characteristics and diagnostic criteria of primary breast lymphoma (PBL). Methods: The cases diagnosed as PBL from January 2009 to March 2015 were collected, their clinical data, and pathological and immunohistochemical features were analyzed, and the diagnosis and differential diagnosis of this condition were discussed with a literature review. Results: All the 8 cases were female, and age of onset ranged from 35 to 82 years. The tumor was located in left breast in 6 cases, in right breast in one case, and in both breasts in one case. The most common presentation was painless mobile mass with distinct borders. Seven cases were diagnosed as diffuse large B-cell lymphoma (DLBCL), and one was diagnosed as mucosa-associated lymphoid tissue lymphoma (MALT). Immunohistochemical staining showed that CD20 and CD79a positive expressions were found in all cases, 7 cases had mum-1 positive expression and 4 cases had Bcl-2 positive expression. After treatment, 4 patients were followed up for 3 to 25 months and all were alive. Conclusion: PBL is a rare condition, and DLBCL is the most common type. Its diagnosis depends on pathological and immunohistochemical examinations. Full awareness of this entity is important for avoiding misdiagnosis.