Introudction Crohn's disease (CD) is a lifelong condition. Multiple imaging investigations are often performed during follow-up. This could cause overexposure to radiation. The aim of our study was to determine mean radiation dose in patients  with  at least a 5-year course of CD and to determine possible risk factors associated with exposure to high doses of radiation. Methods We conducted a retrospective study including patients whose CD was diagnosed between 1998 and 2005. Epidemiologic features of patients, characteristics of the disease,  types of imaging investigations that were performed during follow-up and cumulative radiation effective dose were determined. Risk factors associated with exposure to high doses of radiation were then determined. Results One hundred sixty seven patients were included.  There were 92 males (55.1%) and 75 females (44.9%) with mean age at dianosis of 31.4±12.3years. Global radiation dose was 18.8±18.9 mSv. Twenty seven patients (16,2%) were exposed to more than  35 mSv and 4 patients (2.4%) had an exposure  of more than  75 mSv. Use of Infliximab, age at disease onset ≤ 24 years old and number of flares ≥ 8  were independent risk factors of radiation exposure more than 35 mSv with adjusted Odds ratios (OR) : 2.5 [2.1- 5.3]; 1.6 [1.2- 4.7] and 3.2 [2.1- 7.8] respectively. Similarly,  use of Infliximab and number of flares ≥ 8  were independent risk factors of radiation exposure more than 75 mSv with adjusted OR : 4.3 [2.8-9.5] and 7 [3.2-11.2] respectively. Conclusion Radiation risk seems to be increased with severe course of  CD. Both referring physicians and radiologists have the responsibility to minimise radiation exposure. Entero-magnetic resonance imaging (Entero-MRI)  may reduce this risk.