9543 Background: National guidelines recommend 150 minutes a week of moderate-intensity physical activity for adults with a cancer diagnosis. Our study investigated the feasibility of a self-directed walking in women age 60 or older undergoing cytotoxic chemotherapy treatment for breast cancer. Feasibility was defined as at least 50% of study participants reporting an average of 150 minutes or more of walking/week for exercise or pleasure during the first 6 weeks of chemotherapy. Methods: Eligibility: Female, age 60+; Stage I-III breast cancer; scheduled for chemotherapy; physician permission to engage in physical activity; English speaking. Intervention: Evidence-based physical activity program for adults with arthritis – “Walk With Ease”. Measures: Patients self-reported the average number of days and number of minutes per day of walking for exercise or pleasure during chemotherapy. Study participants also maintained a daily walking diary throughout the first 6 weeks of chemotherapy. Data analysis: Descriptive statistics. Results: Study sample (N = 22): mean age 68 (60-79), 95% Caucasian, 41% high school degree or less, mean Body Mass Index/BMI 31 (20-50), 50% two or more comorbidities. At baseline (pre-chemotherapy), 29% of participants reported walking at least 150 minutes/week. During chemotherapy, the proportion walking > 150 minutes/week: 41% Week 1, 54% Week 2, 32% Week 3, 45% Week 4, 50% Week 5, 45% Week 6. During chemotherapy, the proportion walking > 100 minutes/week: 68% Week 1, 73% Week 2, 77% Week 3, 64% Week 4, 68% Week 5, 65% Week 6. Conclusions: A home-based, self-directed walking program can encourage older female breast cancer to engage in regular exercise during chemotherapy at a level that is higher than pre-chemotherapy. Achievement of the goal of 150 minutes per week is challenging, and more feasible at a level of 100 minutes per week. This pragmatic physical activity intervention is now being tested in a 4-year efficacy trial with a large sample of female breast cancer patients age 65 or older during chemotherapy treatment, to evaluate the impact of exercise on p16INK4a (biomarker of aging), fatigue and other patient-reported outcomes. Clinical trial information: NCT01789983.