The article presents the results of an analysis of the alien flora of the ruderal vegetation of Ukraine. A total of 325 alien species which belong to 58 families and 198 genera were identified. The total anthropogenization index of the ruderal phytocoenoses is 19.8%. It was established that the highest level of anthropogenization was found in the phytocoenoses of Polygono-Poetea annuae, Stellarietea mediae and Plantaginetea majoris. The leading families of the non-native fraction of the studied plant communities were Asteraceae, Brassicaceae and Poaceae. It has been revealed that in the biomorphological spectrum of alien plants therophytes prevailed. The ecological analysis has shown the predominance of submesophytes, acidophytes, semieutrophytes, acarbonatophytes and heminitrophytes plants. It was established that according to the arrival time the kenophytes predominate and by the degree of naturalization – the epoecophytes. Comparison of the alien species composition of the ruderal plant communities by means of Jaccard’s indices showed the most similarity between the classes Polygono-Poetea annuae and Plantaginetea majoris, Robinietea and Galio-Urticetea, Stellarietea mediae and Artemisietea vulgaris. For the separate classes the indices of archaeophytization, kenophytization, modernization and fluctuation of the flora were calculated. It has been established that there are 23 highly invasive species in the ruderal vegetation of Ukraine and among these Ambrosia artemisiifolia, Anisantha tectorum, Grindelia squarrosa, Heracleum mantegazzianum, H. pubescens and Xanthium oreintale ssp. riparium are transformers.
