Objective To evaluate the severity of depression, anxiety, associated risk factors, and cognitive distortion in Korean patients with ulcerative colitis (UC) and Crohn’s disease (CD). Methods This study included 369 patients with inflammatory bowel disease. The severity of depression and anxiety was examined using Patient Health Questionnaire-9 and Hospital Anxiety and Depression Scale. The Anxious Thoughts and Tendencies scale was used to measure catastrophizing tendency. Multivariate regression analyses were performed. Results The predictors of depression were marital status, anti-tumor necrosis factor-α (TNF-α) agent use, age, and body mass index in UC patients and marital status, disease activity, alcohol use, and employment status in CD patients. For anxiety, sex and marital status were the associated factors in UC patients, whereas steroid use was the only significant predictor in CD patients. Comparing the cognitive distortion level, there were no significant differences between UC and CD patients although there was an increasing tendency according to the severity of depression or anxiety. Conclusion If patients are accompanied by high levels of depression or anxiety and their associated risk factors including TNF-α agent or steroid use, it is recommended that not only symptoms are treated but also cognitive approach and evaluation be performed.