Introduction: exposure to ionizing radiation is associated with an increased risk of developing tumors. Patients with Crohn's disease (CD) usually require multiple imaging tests using this type of radiation.Objectives: the objectives of this study were to estimate the total dose of ionizing radiation received by patients with Crohn's disease during their course and to identify the factors associated with higher radiation doses.Methods: two hundred thirty-five CD patients diagnosed between 1972 and 2010 were included. The effective dose (ED) received by each patient was calculated retrospectively based on the number of gastrointestinal transit studies and computed tomography scans performed. Considering recent epidemiological studies, an ED greater than or equal to 50 mSv was used as the cut-off point for increased risk of developing cancer.Results: the mean ED received per patient was 33.4 mSv (95% CI 29.3-37.5). A total of 49 (20.8%) patients received an ED ≥ 50 mSv. The following factors were identified as independent predictors associated with an ED ≥ 50 mSv: Age older than 40 years, need for surgery, age under 16 years at diagnosis and disease duration over 8 years.Conclusions: a substantial proportion of patients with Crohn's disease receive high doses of potentially carcinogenic ionizing radiation. Identification of the most susceptible patients to receive high doses of radiation, monitoring of effective doses received and the use of imaging techniques that do not require ionizing radiation (MR enterography, abdominal ultrasound) could contribute in reducing patients' exposure to potentially carcinogenic ionizing radiation.