Background: Bisphosphonates are the standard therapies used in the prevention of skeletal-related complications in bone-metastatic breast cancer patients. However the optimal duration of bisphosphonate treatment is controversial. Methods: Ninety-nine female bone metastatic breast cancer patients treated with bisphosphonates (zoledronic acid 4mg or ibandronic acid IV 6 mg every 4 weeks or ibandronic acid oral 50 mg / day or clodronic acid 1600 mg / day) for more than two years were evaluated, retrospectively. Results: The median age was 47 (23-71) and (57%) were postmenapousal. Hormone receptor and HER2 were positive in 88 (89%) and 24 (24.2%) patients, respectively. Sixty nine (68.7%) patients used zoledronic acid, 21 (21.2%) ibandronic acid, and 9 (9.1%) clodronic acid as the bisphosphonate therapy. The median duration of bisphosphonate therapy was 3.9 (2.1-16.5) years. Eight (8.0%) patients had complications including osteonecrosis of the jaw in seven and renal failure in one. There was no significant difference in the frequency of complications according to the type or duration of bisphosphonates (p = 0.30 , p = 0.05, respectively).The median follow-up was 6.7 ± 4.3 (2.4-25.8) years. overall survival (OS) was evaluated according to the duration of bisphosphonate. Significant increase in the survival of users for 3.9 (n= 51 ) and 5 years (n= 22 ) (p=0.001 , p<0.001, respectively). None significant difference was found in terms of OS and the time to progression according to the type of bisphosphonate (p = 0.50,p = 0.06, respectively). Bisphosphonate treatment of 36 patients was switched to another kind of bisphosphonate due to the progression of bone metastasis. OS was observed to be better in the subgroups who had bone metastasis progression only and of whom bisphosphanate therapy was switched (p=0.036). Conclusions: In this study we have found that the patients using bisphosphonates for more than 3.9 (the median of the cohort) and 5 years displayed significantly higher survival advantage with the cost of increased rates of osteonecrosis of the jaw. After the progression of bone metastasis, switching the current bisphosphonate therapy to another provided an advantage in survival.