Carnivals in Serbia have a tradition of holding for more than 150 years. By content they belong to the entertainment tourism events. One of the carnivals, taking place over the past 10 years is the Boat Carnival on the river Sava. This carnival is part of the overall tourist offer of Belgrade and by its holding it also promotes nautical tourism on the river Sava. A survey of visitors was conducted to determine the significance of this event in the tourist offer of Belgrade. The study sample consisted of 169 visitors, in random order, different structures. The analysis was done with the aim of investigating the tourism market, attitudes and behaviour of visitors in order to improve the tourist offer. Tourism valorisation of carnivals in Serbia was also done. [Projekat Ministarstva nauke Republike Srbije, br. III47007 i br. 47027III]