There are three options when using a questionnaire in a research study: a) to adopt it, i.e. use a questionnaire with good psychometrical qualities developed by other experts, b) to adapt a questionnaire to a new target population and conditions, e.g. a questionnaire from abroad, c) or to develop a new questionnaire. The first option is preferably recommended as the psychometrical properties of the instrument are known, which saves time and work, and most importantly it enables the comparison of one´s results with other studies. The adaptation of a questionnaire requires (back) translation, items adaptation, experts’ evaluation of items fitting to theory, conditions, and population; cognitive interviews, piloting, confirmatory and exploratory factor analysis, item analysis, internal consistency analysis, and other procedures. A brief step-by-step guide to help with necessary decisions during the process of adapting a questionnaire will be demonstrated.