BACKGROUND: While potential risks of diagnostic medical radiation are acknowledged, actual exposure of patients in routine clinical practice is poorly documented. AIM: To quantify such exposure to vulnerable abdominal organs in patients with inflammatory bowel disease who are already at risk of intestinal cancer. METHODS: All incidences of exposure to diagnostic medical radiation were documented in a consecutive series of 100 patients with inflammatory bowel disease (62 Crohn's disease, 37 ulcerative colitis, 1 indeterminate colitis) attending a hospital-based clinic. Total effective dose (mSv) was calculated using published tables. Predictors of high or no irradiation were evaluated by multivariate logistic regression analysis. RESULTS: Thirteen patients had no documented diagnostic irradiation. Twenty-three patients received an effective dose greater than 25 mSv. An at-risk effective dose >50 mSv was received by 11 patients. Dosage was higher in patients with Crohn's disease than ulcerative colitis (P = 0.02) and in patients undergoing surgery (P = 0.004). However, no predictive factors for high radiation dosage or for no exposure were identified. CONCLUSIONS: At-risk irradiation from diagnostic medical radiation is common in patients with inflammatory bowel disease, and might potentially contribute to the elevated risk of intra-abdominal and other cancers. The level of irradiation should be considered in clinical decisions regarding abdominal imaging.