A sustainable city is a city that functions in such a way that all its citizens are able to meet their own needs without compromising the state of natural systems or the living conditions of other people, both in the present and in the future. In order to make it easier for cities to cope with the challenges posed by the modern way of life, it is necessary to find arrangements for an unencumbered expansion of cities with the rational use of natural and human resources. Rational and efficient use of resources implies quality city management, including methodical spatial planning and urban planning. Rapid and unplanned growth of a city jeopardizes sustainable development when the necessary infrastructure is not developed or when policies are not implemented to ensure that the benefits of city life are equally shared. It is necessary to minimize bad impact on the environment, and pay more attention to air quality and waste management. The main directions of urban sustainability include the following: efficient use of resources; regeneration of natural resources; fewer cars, better access; favorable surrounding for living and housing; sustainable economy; citizen participation and inclusion in the community; preservation of local culture and tradition. The advancement in sustainability implies greater attention paid to the flow of energy and matter through human society and the forecasting of smarter use of natural resources. The paper presents different systems for measuring sustainability indicators and in the empirical part of the paper investigates Mali Lošinj as a sustainable tourist destination. Measures under this article are measured according to the principles of ETIS (European Tourism Indicators System).