In response to the evolution of the information-seeking behaviour of patients and concerns from health professionals regarding cancer patient information, the French National Federation of Comprehensive Cancer Centres (FNCLCC) introduced, in 1998, an information and education program dedicated to patients and relatives,the SOR SAVOIR PATIENT program. The methodology of this program adheres to established quality criteria regarding the elaboration of patient information. Cancer patient information, developed in this program, is based on clinical practice guidelines produced by the FNCLCC and the twenty French regional cancer centres, the National League against Cancer, The National Cancer Institute, the French Hospital Federation, the National Oncology Federation of Regional and University Hospitals,the French Oncology Federation of General Hospitals, many learned societies, as well as an active participation of patients, former patients and caregivers. The handbookSOR SAVOIR PATIENT Cancer and Fatigue is an adapted version of different publications regarding fatigue in oncology. It is meant to provide a basis for the explanationof the disease and to facilitate discussions with the healthcare team. It is available from the FNCLCC (101, rue de Tolbiac, 75013 Paris, Tel. (0033) 1, 01 76 64 78 00,www.fnclcc.fr). This document has been validated at the end of 2005 and published in January 2006. SOR SAVOIR PATIENT guides are systematically updated when new research becomes available. This article is extract from the handbook SOR SAVOIR PATIENT Cancer and Fatigue and concerns the causes and effects of fatigue and how to cope with fatigue. This information allow patients to better understand the causes and effects of fatigue, how to cope fatigue...which represent important patient information needs. This article is meant to inform patients and relatives about the disease and its treatments. It also offers health professionals a synthetic evidence-based patient information source which facilitates discussions with the patient.