The aim of this study is to reveal likely demographic, clinical, and pathological differences among hormone receptor negative breast cancer patients according to their HER-2 status. The medical records of hormone receptor negative breast cancer patients with known HER-2 status between January 1999 and December 2006 were reviewed, retrospectively. A total of 91 cases were included in the study (68 HER-2 negative cases and 23 HER-2 positive cases). The results obtained showed that median age, menarche age, childbearing age, number of children, menopause age, and body-mass indexes were similar in both groups. The HER-2 negative patients had more family history of breast cancer than HER-2 positive patients (13.2% and 0%, respectively, P = 0.091). Eighty-three patients received neoadjuvant/adjuvant chemotherapy. Recurrence occurred in 41 (46.6%) patients. Neither recurrence nor disease-free survival of those patients was associated with HER-2 status. Tumor size (P = 0.042) and number of involved lymph nodes (P = 0.001) were found to be independent prognostic factors for disease-free survival. A tendency for more frequent cerebral metastasis was found in HER-2 positive advanced stage patients (P = 0.052). HER-2 positive patients were less responsive to taxanes (P = 0.071). The number of involved lymph nodes (P = 0.004) and HER-2 status (P = 0.043) were found to be prognostic factors for overall survival. HER-2 positive and negative patients should be followed and treated with different strategies. HER-2 positive patients are at least as resistant to systemic therapies as the HER-2 negative patients. Genetic counseling should be routinely provided to triple negative patients and their families. HER-2 positive patients may be candidates for prophylactic treatment strategies concerning cerebral metastasis.