Inflammatory bowel disease impairs patients' perception of health and has a negative impact on health-related quality of life (HRQOL). Most studies include patients from a single hospital. This may bias limit results through the use of small patient samples and/or samples within a restricted disease spectrum. HRQOL was measured in patients with ulcerative colitis (UC) and Crohn's disease (CD) from 9 hospitals located in different geographical areas in Spain using 2 questionnaires: the Spanish version of the Inflammatory Bowel Disease Questionnaire (IBDQ) and the EuroQol. Results are expressed as medians. The study included 1156 patients (528 patients with UC and 628 with CD; median age, 35 yr; slight predominance of women, 617 versus 539). HRQOL worsened in parallel with disease severity to a similar extent in both UC (IBDQ scores of 6.1, 4.7, and 4.0 for the 3 disease severity groups, respectively) and CD (IBDQ scores of 6.1, 5.0, and 4.1, respectively). A similar inverse relation between clinical activity and quality of life was observed when EuroQol preference values were used. All 5 dimensions of the IBDQ showed significantly lower scores in patients with active UC and CD than in patients in remission. The pattern of scores by IBDQ dimensions differed between patients in relapse (who scored worse on the digestive symptoms dimension) and patients in remission. Variables related with disease activity, time of evolution since diagnosis and female sex, were significantly associated with having a worse perception of HRQOL. The type of disease or geographical area of residence did not influence results on the IBDQ. UC and CD impair patients' HRQOL, and the degree of impairment depends on disease activity but is independent of the type of disease and place of residence.