Cancer cachexia is a severe muscle wasting syndrome associated to cancer and distinct from anorexia, which is often present in this condition. Muscle wasting is exacerbated in cancer patients by chemotherapy treatments. Indeed, chemotherapy itself can induce muscle wasting in animal models in the absence of cancer. Exercise is currently proposed in multimodal therapies for cancer patients. Both endurance and resistance exercise are safe and do not seem to provoke further damage to a frail muscle tissue due to tumor dependent dystrophin downregulation. Through its pleiotropic effects, the benefits of exercise spam from a shift from pro-to anti-inflammatory cytokines, to direct effects on muscle fibers, such as an amelioration of the autophagic flux and pathways involved in protein metabolism. In addition, exercise positively affects the muscle stem cell niche, favoring a pro-myoogenic environment. Since tumor-and chemotherapy-induced muscle wasting share molecular mechanisms, exercise may have the potential to counteract both disease-and therapy-related side effects and to rescue muscle homeostasis.