The aim of this thesis was to research the occurence and placement of foreign invasive plant species along the Ljubljanica river. The work was carried out in the area streching from the Močilnik spring to the Ljubljanica estuary. The area was divided into 87 parts, varying in length, on both river banks. We determined the parts according to the environmental factors and the changes inspecies occurence. Using a questionnaire, we estimated the situation regarding environmental factors and invasive plant species in each part. We noted 21 species from the list of invasive plant species in Slovenia. The most frequent are Solidago canadensis, Solidago gigantea, Impatiens glandulifera in Fallopia japonica, and in water Elodea canadensis. We estimated their presence, occurence, phenological phase, life form, frequency and vitality. With canonical correspondence analysis we proved the connection between environmental factors and the occurence of invasive species, the major part of variability can be explained by the dynamics of the river, the form of the riverbed and the use of land lying immediately next to the river banks. We presented the results graphically and with ordinal diagrams.