Treatments for breast cancer such as chemotherapy or hormone therapy can increase osteoporosis. It seems that exercise training can improve bone mineral density. Therefore, the aim of this study was to investigate the effect of combined exercise training on bone mineral density (BMD) in postmenopausal women with breast cancer. 29 postmenopausal women with breast cancer (58.27 ± 6.31 years) who received surgery, chemotherapy and radiation-therapy and were under hormone therapy at the moment were divided into two groups: experimental and control. Experimental group performed 15 weeks of combined exercise training including walking (2 sessions per week) and resistance training (2 sessions per week on days different from walking days). Control group did not participate in any exercise training. Body weight, body mass index (BMI), Vo2peak and lumbar spines and femur bone density were measured in two groups before and after 15 weeks. Data were analyzed by ANCOVA. Results indicated that after 15 weeks, there was a significant difference in weight, BMI and Vo2peak between experimental and control groups (p<0.05). Body weight and BMI decreased and Vo2peak increased in the experimental group after 15 weeks while there was no significant difference between the two groups in BMD of total lumbar spines (F=2.98, P=0.096) and femur (F=0.95, P=0.147). It can be concluded that 15 weeks of combined exercise training had no positive effect on BMD in postmenopausal women with breast cancer.