The paper is devoted to the monetary circulation of Borysthenes, which was founded in the lower reaches of the rivers Hypanis and Borysthenes, and was one of the earliest Milesian colonies in the northern Black Sea area. In the second half of the 6th century BC, its monetary production consisted of cast bronze coins in the shape of small 'arrowheads' and large trapezoid segments with relief images of an arrowhead and a head of tuna fish on the both sides. If 'arrowhead' money was widespread in the region previously, the segments were found on Berezan and in its vicinity only. The issue of such money, especially those of large face-values, was the purposeful demarche of Borysthenes in the development of its own coin denomination based both on 'arrowheads' and on the weight standard of Cyzicus' coinage. Authorities of the polis appeared to attempt to underline the connection of the new money with the Phocaean weight standard or Cyzicus' coins, taking into account the major orientation of Borysthenes' economy, which was mainly based on trading and handicraft. However, both 'arrowheads' and segments were only the mark of value exchange at a conditional rate. Other cast money of the region in the Late Archaic period was 'dolphins'. They appeared to be the first Olbia polis coins. The foundation of Olbia followed Borysthenes, when, in the last quarter of the 6th century BC, a significant group of new colonists arrived to the region. The social conflict between the first settlers and the newcomers expressed in the form of a dispute between worshippers of Apollo the Healer and Apollo Delphinios. The recovery of social peace in the region was owed to an oracle of Apollo of Didyma; its text was found on Berezan. The expression of the peaceful coexistence of two forms of the cult and two groups of the settlers was obviously permitting the equivalent circulation of different polis coin forms, which were those of 'arrowheads' and 'dolphins' probably authorized by the temples of the two deities. Their symbolism was directly connected to the cults of Apollo the Healer and Apollo Delphinios, who was the patron of the Milesian colonies. Due to military and political instability in the steppe zone of the northern Black Sea area in the second and third quarters of the 5th century BC, Borysthenes lost its political independence, and was transformed into an emporion dependant on the Olbia polis, forfeiting its right to issue its own money. Some part of Borysthenes' population appeared to resettle to Kerkinitis in the northwestern Crimea, which started to issue cast cooper 'arrowhead-fish' and 'arrowhead' money in the 5th century BC.