We report the development of ulcerative colitis (UC) and Crohn's disease (CD) Health Status Scales that improve on existing inflammatory bowel disease (IBD) activity measures by their added association with health status. We surveyed 991 members of the Crohn's and Colitis Foundation of America (CCFA) and analyzed the half with greater disease activity (114 UC, 330 CD, ostomies excluded). Our analysis strategy involved (a) identification of items that discriminated active from inactive disease, (b) factor analysis to reduce the items to clusters sharing common symptom relationships, and (c) regression analysis to select those variables best associated with a composite measure of health status (health care use, daily function, psychologic distress). The factor analyses yielded two indexes for UC and CD: "Diarrhea," and "Other GI symptoms" (Cronbach's alpha 0.59-0.84). The regression analyses for both diseases showed that poorer well-being, the Diarrhea index, and dependence on medication for pain were associated with poorer health status. For UC, lower educational attainment and lower steroid dose, and for CD, the Other GI symptoms index and eye disease, also correlated with poorer health status. By design, the UC and CD Scales are better predictors of health status than the survey version of the CD Activity Index (CDAI), explaining 17 and 21% more of the variance of the health status measure. The final UC and CD Health Status Scales can be used in research and clinical care. They contain symptom items used to assess disease activity and also correlate with health status. Prospective assessment is needed to confirm their accuracy in assessing prognosis and treatment response.