The SU-85 self-propelled gun was developed on the basis of the SU-122, which in turn was structurally based on the T-34 medium tank. From the beginning, the new self-propelled gun was primarily designed as a tank destroyer capable of fighting the German Pz.Kpfw V and VI. Compared to the SU-122, the new Soviet self-propelled gun also received new weapons - the 85 mm gun. The SU-85 vehicles first entered service in late summer 1943 and served on the Eastern Front until the end of World War II. They turned out to be structurally successful vehicles, but their armament was inadequate to counter the Panther and Tiger tanks. Hence, in the course of World War II, the SU-100 was introduced into service. However, shortly after its completion, most of the SU-85 was withdrawn from the Soviet Army and was exported to socialist countries.