Exercise is physical activity that involves repetitive bodily movement done to improve or maintain one or more of the components of physical fitness: cardiorespiratory endurance (aerobic fitness), muscular strength, muscular endurance, flexibility, and body composition. Exercise interventions in patients with cancer have been provided as home-based, patient self-managed programs as well as supervised and unsupervised individual or group exercise sessions of varying duration and frequency. They can include combinations of aerobic and resistance activities. Exercise has been studied in patients with cancer for anxiety, chemotherapy-induced nausea and vomiting, depression, dyspnea, hot flashes, lymphedema, sleep/wake disturbance, pain, and fatigue. It has also been studied for caregiver strain and burden. Users of this information are encouraged to review intervention details in study summaries, as the exercise interventions studied and their timings in the trajectory of cancer care vary and these differences can influence effectiveness.