Introduction: Even though Istanbul is one of the centers of the world’s fastest-growing tourism and travel sector, there are limited statistics on the knowledge, attitudes, and practices (KAP) of travelers from this region regarding travel-related infectious diseases. This study aimed to determine the passengers’ KAP about contagious diseases and contribute to developing new solutions for the problems people face while traveling abroad. Methods: A questionnaire was administered to 182 Turkish travelers planning on traveling abroad and applied to the Istanbul Travel Health Center and the Istanbul Airport Health Control Center between January and March 2019. Results: The proportion of carrying a vaccination certificate was statistically higher in those who received healthcare services at international terminals (P=0.002), especially those who had yellow fever (P