Defining and measuring quality of life is a relatively new dimension of health care for many clinicians. The traditional method of evaluating clinical status and response to treatment has been to look at disease-specific symptoms, global assessments (e.g., impressions of the good, better, or worse condition of a patient), days missed at school, and a variety of disease activity scores. These impressions and techniques may or may not reflect how patients are functioning day to day and how they feel about the illness. To address these issues, health-related quality of life questionnaires have been developed to measure the functional effect of an illness and its treatment on a patient, as perceived by the patient. There are four broad domains that are considered part of a health-related quality-of-life questionnaire: 1) physical and occupational function, 2) psychologic state, 3) social interaction, and 4) somatic sensation. In the case of children, the perception of parents or caretakers may be added to complete the picture. Significant social and psychiatric problems have been described in children with IBD, including absenteeism from school, depression, suicide, and major disruption of family patterns. To understand fully the impact of inflammatory bowel disease and its treatment on patient and family function requires one or more quality-of-life instruments that are sensitive to the full range of symptoms, growth and development, and response (including side effects) to many new therapies.