The article is devoted to the ethnicization of urban space. The process of Verkhneudinsk/Ulan-Ude ethnicization in the context of the nation-building policy, when the Russian city Verkhneudinsk became Ulan-Ude, the capital of the Buryat autonomy is analysed. Nation-building is an urban process, which is impossible outside urban culture and urban relations, without urban strata that form a nation. Ulan-Ude became an instrument of nation-building, necessary for cultivation of modern urban nation in the Soviet version. Former functions did not disappeare, but they were overshadowed by new tasks put by authorities. In this connection the change in ethnic composition did not take place due to displacement of the old one, but owing to massive influx of new, mostly Buryat population. National experiment of the Soviet power combined a thin stratum of Buryat intellectuals and the city, where the Buryats virtually didn’t live. New social and professional groups were purposefullyformed – nomenclature, intellectuals, urban middle classes, workers – through a system of social mobility in the context of socialist industrialization. A new system of education was created, and policy of indigenization was followed. Typical metropolitan set of social and cultural infrastructure – from government structure to museums and theaters, Buryat literary language and national epic, which became basic and unified foundation for the cultural tradition of the nation, were formed as a result.