In the middle 1933 KhPZ had changed production from the BT-2 to the BT-5. The BT-5 tank of the first series was just a slightly modified BT-2 tank but with a new turret in which the 45 mm 20K gun model 1932/38 and the DT machine-gun were installed. The turret has become two-men, and the crew has increased to 3 men.
The design of the tank of essential changes has not undergone. The tank weight has been increased up to 11.5 tones. BT-5 was re-armed with more powerful 45mm Tank Gun Model 1932/38 supplied with 115 rounds for tanks without a radio or 72 rounds for tanks with a radio. The radio station 71-TK-1 had the hand-rail antenna fitted around the turret. Totally 1884 of BT-5 tanks were manufactured in 1933-1934.
During production the turret was slightly changed and the wheel roads were replaced with more light ones. These light road wheels were used to modernise BT-2 as well.
The first usage of BT-5 was in Spain in 1937 where 100 tanks were sent. In May - August 1939 these tanks took part in conflict at Khalhin-Gol as a parts of 6th and 11th Tank Brigade; in campaign in Western Ukraine; in Poland; in Winter War; and at the beginning of the Great Patriotic War. There were many vehicles developed upon BT-5 chassis: bridgelayers, amphibious tanks, radiocontrolled tanks, flamethrower tanks etc.