The usual indices of activity of Inflammatory Bowel Disease fail to evaluate an important aspect of patients' status, their Quality of Life (QOL). A questionnaire dealing with four important aspects of QOL (intestinal and systemic symptoms, emotional and social function) was developed and validated. The questionnaire was administered to 72 healthy controls, 57 patients with Ulcerative Colitis and 55 with Crohn's Disease with different disease severity. Compared to controls, QOL was impaired not only in the more severe forms of disease, but also in patients in remission. In Crohn's Disease, QOL was not closely correlated with the clinical features, thus indicating that the impairment of QOL cannot be inferred from the clinical status and that patients do not "adapt" with the passing of time. The questionnaire allows a more comprehensive definition of the patients' state of health, identifying features which might be underestimated as they fail to emerge from the routine clinical evaluation. A tool of this kind could be used alongside the activity index of disease, both in clinical studies and during routine follow-up.