This chapter explains the existing scientific evidence on the benefits of physical activity in cancer patients. Its combination with traditional pharmacological treatments can significantly increase the results and well-being of patients. We first address the trends in endurance/cardiovascular training based on the frequency, intensity, duration and types of exercise most commonly used. Subsequently, we analyse the evidence related to resistance/strength training and its great progress in recent years in cancer patients. Physical activity is an indispensable element before, during and after the treatment of cancer patients, but it must be correctly designed and adapted to their needs in order to achieve physically active people who enjoy practicing it for life.