This paper presents the chromosome numbers (2n) for 12 alien species collected in the Novosibirsk Region from the families Apocynaceae, Asteraceae, Campanulaceae, Caryophyllaceae, Fabaceae, Lamiaceae, Plantaginaceae, Poaceae. For Asclepias syriaca L. (2n = 22), Veronica filiformis Sm. (2n = 14), Setaria italica (L.) P. Beauv. (2n = 18), and Sorghum drummondii (Nees ex Steud.) Millsp. et Chase (2n = 20), chromosome numbers were determined for the first time on the material from Russia; for Tanacetum parthenium (L.) Sch. Bip. (2n = 18), Campanula persicifoliaL. (2n = 16), and Genista tinctoria L. (2n = 48) – from Asian Russia; for Calendula officinalis L. (2n = 32) and Rudbeckia hirta L. (2n = 38) – from Siberia. Chromosome numbers on the material from the Novosibirsk Region were revealed for the first time for Lapsana communis L. (2n = 14) and Silene noctiflora L. (2n = 24). For all the species studied, brief notes on their general distribution and dispersal in the Novosibirsk Region are provided, along with literature data on chromosome numbers from other regions of Russia.