Background Development of this guideline was undertaken by the Exercise for People with Cancer Guideline Development Group, a group organized by Cancer Care Ontario’s Program in Evidence-Based Care (pebc). The purpose of the guideline was to provide guidance for clinicians with respect to exercise for patients living with cancer, focusing on the benefits of specific types of exercise, recommendations about screening requirements for new referrals, and safety concerns.Methods Consistent with the pebc’s standardized approach, a systematic search was conducted for existing guidelines, and systematic literature searches were performed in medline and embase for both systematic reviews and primary literature. Content and methodology experts performed an internal review, which was followed by an external review by targeted experts and intended users.Results The search identified three guidelines, eighteen systematic reviews, and twenty-nine randomized controlled trials with relevance to the topic. The present guideline provides recommendations for the duration, frequency, and intensity of exercise appropriate for people living with cancer. It also provides recommendations for pre-exercise assessment, safety concerns, and delivery models.Conclusions There is sufficient evidence to show that exercise provides benefits in quality of life and muscular and aerobic fitness for people with cancer both during and after treatment, and that it does not cause harm. The present guideline is intended to support the Canadian Society for Exercise Physiology’s Canadian physical activity guidelines. The recommendations are intended for clinicians and institutions treating cancer patients in Ontario, and for policymakers and program planners involved in the delivery of exercise programs for cancer patients.