Fatigue is a subjective experience that affects everybody. In healthy individuals, it can be considered a physiological response to physical or psychological stress. In people with specific diseases, however, fatigue often represents one of the most significant problems. Fatigue can be caused by many factors, both intrinsic to the patient and extrinsic, such as therapeutic interventions. This review, based on published studies, has been conducted with the aim of presenting a critical discussion of the available information on the characteristics, causes and potential treatments of fatigue in cancer patients receiving chemotherapy. The incidence of fatigue in these patients, the methods for measuring and evaluating fatigue, and possible therapeutic options are discussed. An appraisal of the toxicity of various chemotherapeutic agents is also presented. Although fatigue is now an ever more considered aspect of the toxicity of chemotherapy, it remains difficult to establish what standard should be used to make a quali-quantitative evaluation of this symptom. Furthermore, in the absence of a clear demonstration of the efficacy of some therapies, the management of cancer-related fatigue remains poorly defined (except for the treatment of anemia-related fatigue). New randomized clinical trials are necessary to indicate the best strategies for tackling this important problem.