Background: Patients with inflammatory bowel disease have lifelong needs to learn how to manage their symptoms and life situation. The range of actions that patients take in order to manage daily life and maintain health is referred to as self-care. Assessment of self-care inpatients with inflammatory bowel disease could allow targeted support and education by health care professionals.There are no existing measures assessing self-care in patients with inflammatory bowel disease. Objectives: The aim was to develop and evaluate the self-care questionnaire for assessment of self-care among patients with inflammatory bowel disease. Methods: Qualitative and quantitative methods were used to develop inflammatory bowel disease self-care questionnaire. The development and evaluation process was performed in three phases: (1) item generation based on interviews with patients with inflammatory bowel disease(n=20), (2) content validation in a panel of experts (n=6) and patients(n=100) assessed with the content validity index, cognitive interviews and quantifying and ranking the items to determine the usability of the questionnaire, and (3) final evaluation through a pilot study (n=93) with test-retest evaluation (n=50). An expert review group of three nurses and one physician continuously discussed the result during the development process. Results: A total of 91 patients with Crohn's disease and 102 with ulcerative colitis participated. The final self-care questionnaire consists of 22 items. Assessment of content validity indicated that the items were adequate and easy to understand. Test-retest reliability was confirmed with intraclass correlations above 0.6 after a three week interval, for all items except one. Conclusion: An inflammatory bowel disease-specific self-care questionnaire was developed using structured methods. The evaluation indicated good validity and reliability. The questionnaire may be a useful tool to assess the ability of patients with inflammatory bowel disease to perform routine self-care.