Background: While engagement in PA can lessen fatigue, improve quality of life (QOL) and/or improve survival in cancer survivors, to what extent patients are aware of this and how it affects their behavior is unclear. Methods: 1,244 adult cancer survivors across disease sites and stages (mostly curative) at the Princess Margaret Cancer Centre (PMCC) were surveyed about their perceptions of PA, the barriers that prevent them from being physically active, and their level of PA currently. Multivariable logistic regression evaluated the associations between clinical and socio-demographic factors on these perceptions and current activity levels. Analyses were adjusted for performance status and important covariates. Results: Cancer survivors were surveyed at a median of 26 months after diagnosis. 16% had breast, 12% GI, 26% gyne/GU, 14% head and neck, 6% lung and 19% hematologic cancers. 55% of survivors reported being physically active. Overall, 76% believed PA could lessen their fatigue, 91% reported PA could improve their QOL, and 89% felt PA could improve their 5-year survival. Common barriers to PA were: being too ill (41%), too tired (33%), too busy (29%) and having too many home responsibilities (28%). Older patients were more likely to believe that PA would not improve their fatigue (p=0.005) and not improve their 5-year survival (p=0.001). Lower household income was associated with belief in lack of benefit of PA on fatigue (p=0.0001) or QOL (p=0.02). Not perceiving benefit of PA on fatigue, QOL, or survival was associated with substantially lower levels of PA (p<0.01; each comparison), as was being older and having a lower income (p=<0.01, each comparison). Conclusions: Older patients (even those with good performance status) and those coming from a lower socioeconomic status were more likely to have negative perceptions of the effect of PA on major cancer outcomes, resulting in lower PA levels. At PMCC, we are using this information to shape how we communicate with our patients in our survivorship program to help them with their decision-making on PA.