The Short Inflammatory Bowel Disease Questionnaire (SIBDQ) is a health-related quality of life (HRQoL) tool measuring physical, social, and emotional status (score 10-70, poor to good HRQoL). The SIBDQ has been predominantly used in trials for Crohn's disease, and further validation of the SIBDQ is desirable in ulcerative colitis (UC) patients. The primary objective was to further validate the SIBDQ by examining discriminant ability against measures of disease activity. The secondary objectives were to examine reliability and responsiveness to change. UC patients attending hospital completed the SIBDQ and two activity indices. Patients' disease status (remission, mild, moderate, or severe relapse) was determined subjectively by the patients and their physician. Scores were obtained for 69 events in 61 patients. mean age 47.8 yr (range 16-79). All classes of disease extent were represented. The mean SIBDQ score was 48.4 (13-70). The difference between mean score in patients in remission and relapse was -20.1 (95% CI = -25.1 to -15.1). The difference for remission and mild relapse was -14.6 (95% CI = -8.9 to -20.2). The correlation between SIBDQ and the activity indices were good, r = -0.83 and r = -0.61. Eight patients presented twice. Those with unchanged disease status showed no significant difference in the mean SIBDQ score. Patients whose disease status had deteriorated from remission to mild relapse, or from mild to moderate relapse demonstrated a mean reduction of 11.8 points (95% CI = 20.1-3.4). This study contributes to the validation of the SIBDQ as a HRQoL tool in UC. It is reproducible and responsive to changes in disease activity.