BACKGROUND: Questionnaires are widely used for data collection in travel medicine studies, but there are no validated instruments that are available to researchers in this field. Our objective was to develop and validate a questionnaire to be used in a prospective study designed to estimate the risk of three viral infections in Australian travelers to Asia. METHODS: Qualitative nonexperimental cognitive methods, including cognitive review, task analysis, and cognitive interviews, were selected. A pilot study was performed to assess the instrument in the target population. RESULTS: Recalling dates related to travel or health events was observed and reported to be the most difficult task for travelers. The use of cues embedded into items and provision of memory prompts such as calendars improves the recall of dates during travel. There is a wide spectrum of accommodation, activities, and travel experiences, and item responses that were constructed as lists were useful as memory triggers, particularly for travelers with long and complicated itineraries. Cognitive interviews provided a valuable insight into how travelers used inferential and direct memory to recall travel events and their confidence in the accuracy of these processes. CONCLUSIONS: The development and validation of questionnaires improve the accuracy of the data collected and should be considered an integral part of the methodology of travel-related studies.