The majority of patients with Behçet's disease (BD) suffers from oral ulcers. The aim of the present study was to survey self-rated oral health status, oral function, and oral health behaviour of patients with BD in eastern Japan. Subjects were 33 BD patients and 101 healthy individuals ranging in age from 20 to 59 years. The survey was conducted using a self-administered questionnaire. The items of oral health in the questionnaire included subjective symptoms, self-rated dental problems and oral health behaviour. We found that compared to the healthy subjects, BD patients experienced more severe physical limitations, mainly involving difficulty in pronouncing words (p < 0.01) and the pain of oral mucosa and gingival tissue caused by oral ulcers (p < 0.01). Based on the results of oral health behaviour, BD patients did not behave positively with regard to maintaining oral health including regular tooth brushing despite relatively higher risk of dental diseases that they face. The present results suggest that oral ulcers due to BD induced dental disorder such as the pain of gingiva, oral mucosa, and difficulty in the pronouncing of words. In spite of this, their oral health behaviour is not positive compared to the healthy subjects. Thus, the need to develop a more active pragramme for oral health education for patients with BD is indicated.