Ulan-Ude is the capital city of the Republic of Buryatia, Russia, located about 100 kilometers (62 mi) southeast of Lake Baikal on the Uda River at its confluence with the Selenga. According to the preliminary results of the 2010 Census, 404,400 people lived in Ulan-Ude; up from 359,391 recorded in the 2002 Census. In terms of population, it is the third largest city in eastern Siberia.

Ulan-Ude has 14 sister cities.