Nautical tourism in the world, as well as in The Republic of Croatia, has significantly increased in the last decade. There are three basic types of nautical tourism: nautical tourism ports, charter and cruising. Development of nautical tourism brings increased numer of vessels and new nautical ports which causes pressure on the environment. Nautical tourism ports are one of the largest users of marine waters and coastline. In pursuing their efficient development they should strive toward the protection of the environment. This work explores pollution on the marine environment, especially the negative impact of cruising. Cruising ships generate a number of solid waste, hazardous waste, black and gray wastewater, oily bilge water and ballast water. This work present quantity and quality analyses of nautical tourism in The Republic of Croatia. The growing demand pose new challenges for the future development of the nautical tourism in the Republic of Croatia. It is very important to prevent negative impact upon the marine environment and find sollutions for the successful sustainable development of nautical tourism.