Monitoring the presence of invasive species in natural wetlands is crucial for nu- merous reasons, including their negative impact on biodiversity, conservation and the ecosystem services provided by these important fragile areas. The aim of this paper was to investigate the presence and distribution of the highly invasive liana Echinocystis lobata (wild cucumber), and to determine its coenological relations with the native plant species in the Ramsar sites of the southern part of the Pan- nonian Plain (the southeastern part of Central Europe, northern Serbia). We con- ducted the phytocenological research of the selected protected riparian areas in detail over a six-year period (2011-2015 and 2020). This study revealed the signifi- cant presence of the highly invasive species E. lobata in the studied sites. Wild cu- cumbers were found in 146 plots in four out of the seven investigated areas. Cluster analyses distinguished four groups of releves dominated by E. lobata, which were described, and their dominant and constant species were identified. Habitat type identification was done, and the habitat preferences of E. lobata were determined. The spatial distribution of the four groups is such that they occur in a number of different habitat types or local communities. The species pool which makes up each of these four groups is thus geographically larger than the local community under study, so we can treat them as independently established and well-defined new community assemblages. Plant communities dominated by the invasive spe- cies E. lobata have not been described previously. Therefore, this work provides new data, and contributes to the further research and comparative analyses need- ed to describe invasive plant communities dominated by wild cucumber. In addi- tion, the identification of habitat types which are most occupied by E. lobata is very important for managers of protected areas, as it allows them to better control and remove this highly invasive species, but also to prevent its further spread.