Background and aims We investigated the beliefs and behaviours about tobacco among inflammatory bowel disease (IBD) patients. Materials and methods A questionnaire of 18 items was developed and administered to all consecutive patients followed for IBD at Nancy University Hospital from October 2012 to March 2013. Results Two hundred and thirty-one patients participated in the survey [Crohn’s disease (CD)=171, ulcerative colitis (UC)=60]. Among IBD patients who were smokers at diagnosis, 10.5% of CD patients versus 14.3% of UC patients believed that tobacco could have triggered their IBD; about half the CD smokers at diagnosis were not aware that smoking might promote their disease. Three quarters of smokers after diagnosis knew that tobacco was not beneficial for their CD, whereas all UC were aware that smoking had a beneficial effect on their disease course. About half of the CD patients had stopped smoking during a flare-up. Four former smokers with UC (21.1%) resumed smoking during a relapse. Nearly 90% of IBD current smokers wished to quit smoking. About half the IBD patients were aware of the relation between smoking and IBD, and the Internet was a source for 24.3% of these patients. Conclusion The majority of IBD patients are unaware of the effects of tobacco on their disease. Better information through a therapeutic education programme should be systematically recommended in IBD.