BACKGROUND AND AIMS: Given the impact of anxiety and mood disorders on health, it is important to consider these disorders in persons with inflammatory bowel disease (IBD). We assessed the prevalence of anxiety and mood disorders in a population-based IBD cohort. METHODS: A structured diagnostic interview was administered to participants in the cohort (N = 351), and rates were compared to age-, gender-, and region-matched controls drawn from a national survey (N = 779). RESULTS: A comparison of lifetime prevalence suggests higher rates of panic, generalized anxiety, and obsessive-compulsive disorders and major depression and lower rates of social anxiety and bipolar disorders in the IBD sample than in national samples in the United States and New Zealand. Direct comparisons with matched controls (with data available for three anxiety disorders) found lifetime prevalence (IBD vs controls) as follows: social anxiety disorder lower in IBD (6%vs 11%, OR 0.52, 95% CI 0.32-0.85), panic disorder not significantly different (8.0%vs 4.7%, OR 1.59, 95% CI 0.96-2.63), agoraphobia without panic not significantly different (1.1%vs 0.6%, OR 1.44, 95% CI 0.37-5.55), and major depression higher (27.2%vs 12.3%, OR 2.20, 95% CI 1.64-2.95). Comparing IBD respondents with and without lifetime anxiety or mood disorder, those with a disorder reported lower quality of life and earlier onset of IBD symptoms and there was a trend toward earlier IBD diagnosis. CONCLUSIONS: Clinicians should be aware of the increased prevalence of depression and possibly other anxiety disorders in persons with IBD as these disorders may influence response to treatment and quality of life.