Few data is available on the Quality of Life (QoL) of Crohn Disease (CD) patients. OBJECTIVES: to assess the QoL of CD patients prospectively over one year and to determine possible factors of influence. Methodology: At MO, M3, M6, M9 and M12, patients had to fill a self-administered QoL questionnaire. Investigators completed a clinical form referring to the period of 3 months prior to the visit. The QoL questionnaire was made up of the SF-36 and the RFIPC (questionnaire specific to inflammatory bowel disease). The correlation between QoL and the evolution of the disease was assessed by both patients and investigators by the mean of a visual analogue scale. RESULTS: 231 CD patients were included by 19 centres from the GETAID: they were 33 years old on average, 57% were women, 47% were smoking. Patients had CD for 8.7 years on average. At M0, the SF-36 scores of CD patients were significatively lower than those of a standard population. Nevertheless, the CD patients scores improved over time. The main worries of CD patients, as measured by the RFIPC, were "having an ostomy bag", "uncertain nature of the disease", "energy level" and finally "having surgery". Correlation of patients' assessment of the evolution of CD and QoL was significatively higher than that of the investigators. Significant factors of an impairment in QoL were: gender, smoking habits, active CD, hospitalisation, and surgery in the past 3 months. Conversely, in-take of immunosuppressive drug was a significant factor of QoL improvement. Impact on QoL of medical treatment was not related to activity of disease. CONCLUSION: Patients' QoL is impaired by CD and such impairment is probably underestimated by clinicians. Smoking habits, hospitalisation and use of corticoids, which are factors known as having a negative impact on QoL, could be acted on. Conversely, the use of immunosuppressive drug could be prompted considering its positive impact on QoL.