Aim To determine the effects of exercise training that was supported with follow-up calls at home on the postoperative level of physical activity and quality of life of women with breast cancer. Methods The study was carried out with a quasi-experimental design. Women who had underwent an axillary dissection and mastectomy and who were receiving ongoing chemotherapy treatment in the ambulatory unit of a university hospital were included in the study. Sixty-two women were randomly assigned to an intervention (n = 31) or a control (n = 31) group. The women in the intervention group were given exercise training and then they were followed up by phone calls at home for 12 weeks in order to ensure the continuity of the exercises. Results At the end of the study, the number of "very active" individuals and the "total physical activity level" increased significantly in the intervention group but decreased significantly in the control group. In the intervention group, "future healthy function" in the functional area subscale significantly increased but "systematic therapy side-effects," "breast symptoms," and "arm symptoms" in the symptom subscale increased significantly. Conclusion Exercise training that is supported with home follow-up calls after surgery increases the level of physical activity, which then favorably relates with a good quality of life of women with breast cancer.