OBJECTIVES Crohn's disease (CD) causes inflammation in the lining of the small or large intestine and is characterized by disease flares. This study quantified the incidence of disease flares among adult patients with CD, and assessed the impact of flares on resource utilization. METHODS Cross-sectional data were collected via the Inflammatory Bowel Disease (IBD) Study Project during Q3 2008. Study participants were recruited from an Internet panel and were reported to have IBD as diagnosed by a physician. All survey respondents were aged ≥18 years. RESULTS A total of 500 patients with CD completed the survey. Overall, 32.0% of all CD patients reported one or more flares per week, while an additional 26.8% reported one or more flares per month. Patients reporting one or more flares per week were significantly younger (42.2 years) and had CD for shorter lengths of time (11.7 years) than patients with less frequent disease flares. The former were more likely to classify their disease as moderate to severe, uncontrolled, and more bothersome. The majority of disease flares lasted less than one week and were of moderate severity. Patients experiencing more frequent disease flares were significantly more likely to have been hospitalized (28.8% vs. 6.5%), have longer lengths of stay (2.2 days vs. 0.9 days), visited the emergency room (40.6% vs. 6.5%), and visited their gastroenterologist (60.6% vs. 32.3%) in the past six months as a result of their CD. These patients were also more likely to have higher degrees of work productivity loss. CONCLUSIONS The majority of patients with CD experience disease flares at least monthly, and the more frequent the flares, the greater the resource utilization and disruption to work life. Treatments that adequately control disease flares may result in cost offsets and should be examined.