Fluvial relief is one of the most prevalent morphogenetic type of relief in the Republic of Croatia. For researching the geomorphology of small streams, the available cartographic bases are not sufficiently detailed (small scale maps). The aim of this thesis is to utilize an unmanned aerial vehicle (commonly known as a drone) with an RGB camera to gather high – quality data on the geomorphology of a small watercourse. The area of research is the Svibanj stream near Jastrebarsko. The research area is divided into a wider and a narrower research area. In the wider research area, based on available data and maps, morphometric analyses of the drainage basin, drainage network and stream bed of stream Svibanj were conducted. In the narrower research area morphometric analyses of a part of the stream bed were conducted based on orthophoto map and digital surface model (DSM) obtained from images collected by an unmanned aerial vehicle. The new condition of the stream bed was compared with the old condition, which is based on data from the Croatian Base Map (HOK). In the narrower research area basic fluvial processes and anthropogenic influences are also described. The research provided new knowledge about the geomorphological characteristics of the Svibanj stream, especially the characteristics of its stream bed. Also, the advantages and disadvantages of using an unmanned aerial vehicle in such researches have been observed.