Though seemingly an ordinary and unexciting machine with superficial close similarity to Britain's Fairey Battle (which proved a disaster), the IL-2 was almost certainly built in larger numbers than any other single type of aircraft. Output averaged 1,200 per month during most of World War II, to give a total of approximately 36,000. When the IL-10 developed version is added the total is reported to amount to 42,330.

Designed as an armoured ground-attack and anti-tank aircraft, the prototype (designated BSh-2 from Bronirovanni Shturmovik, armoured attacker) flew for the first time on 30 December 1939. It looked like a larger edition of one of the single-seat fighters of the period and was powered by an AM-35 engine. Apart from the wooden rear fuselage it was all-metal, and the area round the engine and cockpit was actually constructed from 700kg of steel armour, offering excellent protection against fire from the ground. On 12 October 1940 the TsKB-57 took to the air with the more powerful 967kW M-38 engine. This improved machine led to the IL-2 which was just getting into service when the Germans invaded in June 1941.

Armament of the original IL-2 was two 20mm ShVAK and two 7.62mm ShKAS guns firing ahead, plus eight 82mm rockets and four 100kg bombs. The need for rear protection resulted in a second crew member being added to man a rear gun, usually a 12.7mm BS, and the forward guns were changed to the hard-hitting 20 or 37mm VYa, and sometimes two of each. Bomb load went up to 600kg, including PTAB armour-piercing bombs. The Shturmovik's weapons could pierce all German armoured vehicles, even the Tiger tank being vulnerable when attacked from the rear. Swarms of these tough aircraft are judged by the Soviet Union to have played the dominant role in air warfare on the Eastern Front. IL-2 remained in operational service in the Soviet Union and with the Air Forces of Czechoslovakia and Poland into the 1950s. Indeed Stalin commented that the IL-2 was 'as essential to the Soviet Army as air and bread'.