Bradshaw indices. Correlation among scores of SIBDQ, EuroQol, Psychological General Well Being Index and clinical indices of activity were all positive and comparable for both diseases (r=-0.50 to r=-0,70, p<O.01). Analysis of the variance showed that SIBDQ discriminates between different clinical degrees of activity. Cronbach's a was 0.96 both in ulcerative colitis and in Crohn's disease. SIBDQ was also highly reproducible when repeated in clinically stable patients with ulcerative colitis (ICC = 0.82) and Crohn's disease (ICC = 0.86). Furthermore, SIBDQ was sensitive to clinical changes in ulcerative colitis and in Crohn's disease, whether patients entered remission (effect size -1.88 and -1.81 respectively) or relapsed (effect size 1.70 and 8.04 respectively). In conclusion, the Spanish version of the IBDQ is a valid, reliable and sensitive instrument to measure quality of life of patients with ulcerative colitis and Crohn's disease and to detect clinical changes during the course of the disease.