The aim of this paper was to map distribution of selected invasive neophytes in the Protected landscape area Dunajské luhy (West Slovakia). The paper is focusing on some of the most damaging invasive plant species (two trees Ailanthus altissima and Negundo aceroides, one herb Fallopia japonica), ranked among the most disturbing species in Europe, as they penetrate into natural vegetation irreversibly changing its structure, in relation to the main driving factors of change. We mapped stands of selected invasive neophytes and measured selected population-biological characteristics of F. japonica (population density, high of plants). In 2015, invasive plant species colonized total area of 16,338 m2 (146 populations) in the studied area of the floodplain forest in the Protected landscape area Dunajské luhy. In comparison with the observed taxa, species A. altissima formed bigger number of populations (122) and colonized bigger area (13, 803m2). The distribution of the invasive plant species was observed on 84% of the studied sites. Other species found on the sites included F. japonica on an area of 2, 080m2 (19 populations), N. aceroides on an area of 455 m2 (5 populations). Polynomic trend was found between the size of the area and population density of F. japonica (r= 0.73).