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The key events in the history of the antique city of Tanais were considered against a background of the climate change starting from the 3rd century BC and ending at the 5th century AD. For reconstructing climatic changes during the city existence, we used palynological, microbiomorphic and paleopedological analyses of paleosols and cultural layers of Tanais and neighboring settlements. The antique city was located on the right bank of the Tanais (Don) River near its entering the Sea of Azov and exercised trade and economic relations with the barbarian (nomadic) population that inhabited the steppes near the Don River and the Sea of Azov in the Early Iron Age. It was shown that the foundation of Tanais in the 3rd century BC and its growth through the 2nd century BC took place in climatic conditions, comparable to those of the modern period. The most devastating conquest of the city by Bosporus King Polemon occurred in the late 1st century BC, when the climate aridity reached its peak and the city of Tanais probably suffered from an economic crisis. The study of the chronosequence of soils buried under stone walls of the city and other settlements nearby at different times revealed a decrease of organic carbon and an increase carbonate and gypsum contents in the paleosols since the 3rd century BC till the beginning of the 2nd century AD. Those data confirm a strong climatic aridization at the turn of the eras. As follows from the pollen analysis, throughout the whole period of the city existence it was surrounded by steppe communities, but the coniferous (pine) pollen was also found in the spectra of all chrono-intervals. The highest proportion of pollen of cultivated plants and weed (4-6%) is found in the assemblages attributable to the first period of the city life (the 2nd-1st centuries BC). The analysis of microbiomorphs agreed with the pollen data and provided additional data on the wood and reed having been widely used in economical activities of population in the first period of the city existence. From the middle of the 2nd to the late 4th centuries AD the climate conditions may be considered to be humid and favorable for bioproductivity. Another wave of aridity was recorded at the boundary of the 4th and 5th centuries AD. At the end of the 5th century AD the city ceased to exist.