Tourism is a growing economic activity that in many countries, including Croatia, brings great profits and profits throughout the year. Tourists also, either alone or in cooperation with certain organizations, organize a trip to a tourist destination, for the purpose of rest, recreation and other reasons, and often use the benefits of an organized arrangement, i.e. the services of a tour operator. They act in the market as organizers, coordinators and implementers of the interests of the offerors and users of the tourist product, in order to provide appropriate services, for the purpose of mutual satisfaction. One example of a tour operator is Thomas Cook, which went bankrupt a few years ago, after which, due to the COVID-19 pandemic, it started operating exclusively as an online tour operator, which today provides its services exclusively in such a format, thanks to investors. Thomas Cook is such a good example of relatively bad business in recent years, that is, a good example for other tour operators who can learn from his mistakes. The subject of this paper is therefore to show the basic functions of tour operators and explain how the bankruptcy and downfall of Thomas Cook went, as well as what can be learned from the above.