Background & Aims: Clostridium difficile-associated disease (CDAD) rates have been increasing. We sought to determine whether CDAD incidence has increased specifically in hospitalized patients with IBD. We also explored possible differences in the risk for and time to presentation of CDAD between IBD and non-IBD patients. Methods: We analyzed hospital admissions from 1998-2004 for demographics, length of stay, C difficile infections, and time from admission to a positive C difficile test. We calculated CDAD incidence for non-IBD, all IBD, CD, and UC admissions and used logistic regression to estimate the risk for CDAD. Results: CDAD incidence increased in each group and was higher in all IBD than non-IBD groups. During the observation period, CDAD rates approximately doubled in CD (9.5 to 22.3/1000 admissions) and tripled in UC (18.4 to 57.6/1000). Length of stay was similar among the groups. For all years combined, the adjusted odds ratios for CDAD in all IBD, CD, and UC admissions were 2.9 (95% confidence interval, 2.1-4.1), 2.1 (1.3-3.4), and 4.0 (2.4-6.6), respectively. The median times from admission to a positive C difficile test result for non-IBD, CD, and UC were 4.0, 0.8, and 0.5 days, respectively. Conclusions: CDAD incidence in IBD has increased and is higher than in the non-IBD population. IBD and UC patients in particular have a higher risk for CDAD. C difficile infections in IBD are confirmed predominantly within 48 hours of admission, suggesting most were acquired before hospitalization.