The subject of this paper is sustainable development planning in the Lonjsko polje Nature Park. Lonjsko Polje Nature Park is one of the protected areas of Nature Parks in Croatia. The aim of this paper is to describe the Lonjsko Polje Nature Park and its tourist resources, as well as the analysis of previous development plans and setting guidelines for future sustainable development. For that purpose, the analysis of the Development Strategy of the Lonjsko Polje Nature Park as a master plan in the period from 2014 to 2020 was performed. The analysis showed that it is a very sensitive natural area with extremely valuable biodiversity of flora and fauna as well as a special cultural and historical heritage (old wooden houses, folklore). Although the destination Lonjsko polje Nature Park is being developed in accordance with the Development Strategy and Plans, there are still new opportunities for sustainable development. This primarily refers to the protection and preservation of natural resources that need to be developed in accordance with the principles of sustainable development: environmental, socio-cultural, technological and economic principles. The guidelines for the sustainable development of the Nature Park propose the use of renewable energy sources in order to permanently protect the resources of the Lonjsko Polje Nature Park.