The increasing number of heavy German tanks such as the Tiger and Panther in 1943 gave the Soviets pause for thought, especially after the tank clashes at Kursk. Front-line tank commanders now felt the T-34's 76.2mm gun was inadequate when pitted against the German's new big cats.

Development of a T-34 replacement, the T-43, was cancelled and work was set about to fit the existing 85mm anti-aircraft gun to a T-34. To fit the larger gun a larger turret and turret ring (from 1425mm to 1600mm) had to be accommodated on the T-34 hull. This required retooling of the factories. The T-43's turret design was hurriedly adapted to fit the T-34.

The resulting new T-34/85 tank had a much superior gun and finally, a three-man turret.

The new stopgap model still retained the radio in the hull, but this was remedied later with the obr 1944. With a three-man turret the commander could just command the tank, leaving the operation of the gun to his gunner and loader.

The new tank was the T-34/85 obr 1943, it was only put in production for a short period (February March 1944) and was armed with the D-5T 85mm gun rather than the ZiS-S-53 85mm gun of the 1944 model.

The T-34/85 obr 1943 turret displayed a unique style of bolted collar. This interim model also featured a rounded front-hull joint, rounded front fenders and no turret fillet. Approximately 800 T-34/85 Model 1943 were produced at Gorky in early 1944.

Due to the bad positioning of the cupola (over the gunners position) many T-34/85 obr 1943 went into service still with only two turret crew.

However, some units managed to pressgang extra crewmen from anti-tank rifle units to bring the turret crew up to three.

The T-34/85 was still not a one on one match for a Panther, but the Soviets always have numbers on their side. Its improved firepower helped to level the playing field. The decision to improve the current T-34 model rather than launch into the production of a whole new production series (though the T-43 did still retain 70% parts compatibility) retained the Soviets' overwhelming numerical advantage.

In May 1944, the Wehrmacht had only 304 Panthers operating on the Eastern Front, while the Soviets increased T-34-85 production to 1200 tanks per month.

The improved T-34/85 remained the standard Soviet medium tank with an uninterrupted production run until the end of the war.