Until recently hydrological heritage has practically existed in science neither as an idea nor a subject. Definitions of the main terms, general classification of hydrological heritage, as well as expanded classification of hydrological heritage of Serbia are presented in the paper which is the starting point needed for further determination of new direction in hydrology and geoheritage. The paper has also pointed to the key reasons for the previous unfavourable status of hydrological heritage and its scientific and national significance, as well as the necessity of its existence and complex development.