The dataset, “Biodiversity of urban floras of the Urals and Volga region”, includes data on the composition of 19 urban floras located in the Sverdlovsk, Samara and Ulyanovsk regions, the Republic of Bashkortostan and the Udmurt Republic. The studied cities, according to the classification adopted in the Russian Federation, differ in population size into: small, with a population of less than 50,000 people (Kambarka, Krasnoufimsk, Mozhga, Novoulyanovsk, Sengiley, Turinsk), medium, with a population of 50,000-100,000 people (Votkinsk, Zhigulevsk, Ishimbai, Kumertau, Meleuz), large, with a population of 100,000-250,000 people (Dimitrovgrad, Kamensk-Uralsky, Salavat, Sterlitamak), very large, with a population of 250,000-1,000,000 people (Izhevsk, Tolyatti, Ulyanovsk) and a city with a population of over 1 million people – Yekaterinburg. In the urban flora 2050 plant species were recorded, and synonymy was aligned with The Plant List (http://www.theplantlist.org). The dataset provides information about the distribution of each species in studied urban floras as well as grouping of species into native plants, neophytes and archaeophytes. The general list of vascular plants of the analyzed urban flora is compiled on the basis of the authors' own field research. All types of habitats (natural, semi-natural and artificial) were examined. Our direct observations were supplemented with information from herbarium collections: the Museum of the Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences (SVER), Ural Federal University (UFU), Kurgan State University, Udmurt State University (UDU), South Ural Botanical Garden-Institute, Institute of Ecology of the Volga River Basin of the Russian Academy of Sciences (PVB RAS). Published sources were also consulted (Ilminskikh et al., 1998; Rakov, 2003; Rakov, Saxonov, 2008; Kornilov et al., 2012; Mogutova Mountain..., 2013; Rakov et al., 2013; Golovanov, Abramova, 2014a; 2014b; Baranova, Bralgina, 2015; Golovanov et al., 2015; Golovanov et al., 2017; Golovanov, 2018). In the general list of vascular plants, native and alien species were identified. Alien species are understood as plant species either unintentionally introduced into our region as a result of human economic activity, or as ornamental or purposefully introduced species found outside their cultivation areas (Tretyakova, Shurova, 2013; Baranova et al., 2018). Alien species, depending on the time of their appearance in the flora, are traditionally divided into two groups: archaeophytes and neophytes (Pysek et al., 2004). Archaeophytes are alien species that appeared in the study area before 1800, neophytes appeared after this date. The main sources for classifying archaeophytes and neophytes into groups were complete lists of flora of the Sverdlovsk Region (Knyazev et al., 2016; 2017; 2018; 2019a; b; 2020; 2021) and the Udmurt Republic (Baranova, Puzyrev, 2012), as well as lists of alien plants of the Samara and Ulyanovsk regions (Senator, Vasyukov, 2019), the Republic of Bashkortostan (Muldashev et al., 2017). The analysis also uses data from K. F. Ledebour (von Ledebour, 1842-1853), K. K. Klaus (Klaus, 1852), p. Korzhinsky (Korzhinsky, 1898), H. F. Lessing (Lessing, 1835), A. A. Bunge (Bunge, 1851), Y. K. Schell (Schell, 1880; 1883), O. and B. Fedchenko (Fedchenko, Fedchenko, 1894), which summarized information about the flora of the Urals and the Volga region, accumulated by the beginning of the XIX century. In order to provide a single classification scheme in which each species is assigned to only one category, we used the approach described by La Sorte and co-authors (La Sorte et al., 2008). Species that were not identified exclusively as native were classified as archaeophytes if they were identified as archaeophytes in at least one urban flora. Similarly, species have been classified as neophytes if they have not been identified as archaeophytes in any urban flora and have been identified as neophytes in at least one urban flora. At the same time, preference is given to assigning an alien status to a species, because such species show the ability to settle in a secondary area. Among alien plants, preference has been given to the status of archaeophytes, due to their earlier appearance in new regions outside the primary range. Accordingly, species have been universally identified as archaeophytes if they are classified as archaeophytes in at least one urban flora (La Sorte et al., 2008).