Aliment Pharmacol Ther 2011; 33: 707-713 Summary Background Although thiopurines are considered safe in humans, they are still pregnancy FDA category D drugs. Prevention of post-operative recurrence is a challenge in clinical practice in Crohns disease. The European Crohns and Colitis Organisation consensus states that thiopurines should be considered in high-risk patients. Aim To perform a worldwide survey for evaluating the extent to which gastroenterologists who are experts in the field of IBD are utilising thiopurines during pregnancy and in the post-operative setting in Crohns disease. Methods This was a Web-based cross-sectional, statement-based survey, which was conducted among experts who have published at least once in the field of thiopurines in IBD. Results Between 20 December 2009 and 9 April 2010, 175 questionnaires were received. The median number of IBD patients per physician per year was 400 (IQR 25-75th, 188-600) and the total number of IBD patients followed by all responders was 82 379. In a pregnant woman with a history of severe Crohns disease in clinical remission after 1 year on azathioprine, 89% of experts usually continue azathioprine until delivery and 9% of physicians never administrate azathioprine during pregnancy. After ileocecal resection for Crohns disease, 39% of physicians initiate azathioprine only in high-risk patients, 28% of practitioners prescribe azathioprine according to endoscopic evaluation, 20% of gastroenterologists systematically initiate azathioprine and 13% have a different attitude. Conclusions Almost 9 of 10 physicians continue azathioprine throughout pregnancy. About 7 of 10 physicians prescribe azathioprine in the post-operative setting according to the European Crohns and Colitis Organisation recommendations, whereas one-fifth of practitioners systematically initiate azathioprine after surgery.