136 Background: Women with metastatic breast cancer may survive for many years after disease onset, and there is little published evidence on their habitual levels of physical activity. The aim of this study was to investigate differences in physical activity levels and physical fitness between women with and without metastatic breast cancer. Methods: Seventy-one women with metastatic breast cancer (METS) aged 57.7 ± 9.5 y and 2.9 ± 3.1 y after disease onset, and 71 healthy controls (CONTROLS) aged 55.0 ± 9.4 y participated. Of those with metastatic disease, 27% had metastases in bone only, 35% in viscera only and 38% in both bone and viscera. Strength was measured using hand and leg dynamometry, aerobic fitness using the Modified Canadian Aerobic Fitness Test, and fatigue with the FACT-Fatigue questionnaire. Participants wore a SenseWear physical activity armband over 6 days, and the average steps taken per day over 5 of these days, where there was a minimum wear time of 8 hours per day, was derived. Results: METS possessed lower aerobic fitness than CONTROLS (25.3 ± 5.4 versus 31.9 ± 6.1 ml·kg·min^-1 respectively; p<0.01). METS were significantly weaker than CONTROLS. Lower limb strength for the METS and CONTROLS was 53.8 ± 23.7 versus 76.0 ± 27.4 kg and handgrip strength was 26.6 ± 6.0 versus 30.2 ± 6.4 kg. METS were also significantly less active, attaining only 57% of the daily step counts of CONTROLS. Fatigue was significantly higher in women with metastatic cancer compared to their healthy counterparts (38.0 ± 9.8 versus 46.3 ± 4.6; p<0.01). Correlation between fatigue with average steps per day (r=0.46), handgrip strength (r=0.29) and leg strength (r=0.26) was low in the METS group. Conclusions: Women living in the community with metastatic breast cancer are weaker, have lower aerobic fitness, and are relatively inactive compared to their healthy counterparts. Increased fatigue in these women is poorly associated with their decreased physical activity levels, hand and lower limb strength. Women with metastatic breast cancer may benefit from a program directed at improving their strength and fitness. Acknowledgements: Funded by National Breast Cancer Foundation, Australia.