The purpose of the doctoral thesis entitled "Optimisation of selection of the location and facilities of a nautical tourism port'' is to define physical capacities and limitations and to propose criteria for optimal selection of the location and of the facilities of a nautical tourism port. General and special aims of the research have been set which, in terms of the set problem, require the application of multi-criteria analysis. The structure or the definition of the problem is the most important characteristic in view of the possible support methods and procedures for making decisions about a particular problem. Well structured problems have been successfully resolved by applying optimisation techniques and methods and other econometric methods, but if the problems are partially or insufficiently structured it is necessary to orient to the new concept of support to the decision-making process and to the new generation of mathematical methods which allow for multi-criteria approach to problem solving. In this paper, the author accentuates the systematic approach to the analysis of the factors affecting the selection of the location and facilities of a nautical tourism port. Their interrelation and effects that provided grounds for the design of physical and technological-economical model of a nautical tourism port for the purpose of sustainable development have been analysed. The criteria for the selection of the location and facilities of a nautical tourism port have been determined, and their evaluation resulted in deciding about the selection of the optimal solution. The author presented the methods of multi-criteria analysis for the purpose of selection of the location for a nautical tourism port: first a general model is defined and then, in an example of the selection of location for a nautical tourism port in the North Adriatic, an analytical and graphic presentation of solutions using Decision lab software for PROMETHEE method and Expert Choice for AHP method are given. The use of GAIA method for the visualisation of problem characteristics through geometric interpretation and presentation of the results ofthe multi-criteria analysis are pointed out. The results of multi-criteria analysis are elaborated in verbal and graphic interpretation of the obtained ·Ievels. The research indicates the importance of systematic conception and acceptance of integral management of the sea and littoral environment as factors of sustainable development. The accommodation capacities of nautical tourism ports and physical development concept have been determined. Through defining the criteria, determining weighted coefficients and comparing the obtained alternatives, the optimisation model of the selection of the location and facilities of a nautical tourism port has been established. The verification of the application of optimisation model for selecting the location and the facilities, implementing methods of multi-criteria analyses and has been done on specific examples with special attention given to applicability to any location of a nautical port. The implementation of the model allows attaining the quality and efficiency of business operations of a nautical tourism port - the holder of the development of nautical tourism and element of integral management of maritime domain.