It was then used successfully by the Japanese during the Second Sino-Japanese War. When Italy entered war in 1940, the BR.20 was the standard medium bomber of Regia Aeronautica (Italian Air Force) but it was already showing its age. By 1942, it was mostly used for maritime patrol and operational training for bomber crews. More than 500 were produced before the end of the war.
In 1934, Regia Aeronautica requested Italian aviation manufacturers to submit proposals for a new medium bomber; the specifications called for speeds of 330 km/h (205 mph) at 4,500 m (15,000 ft) and 385 km/h (239 mph) at 5,000 m (16,400 ft), a 1,000 km (620 mi) range and 1,200 kg (2,600 lb) bombload. Although Piaggio, Macchi, Breda, Caproni and Fiat offered aircraft that mainly exceeded the speed requirements (but not range), not all exhibited satisfactory flight characteristics or reliability. Accepted among the successful proposals, together with the trimotor Savoia-Marchetti SM.79 and Cant Z.1007, was the BR.20 Cicogna designed by Celestino Rosatelli, thus gaining the prefix BR, (for "Bombardiere Rosatelli").
The BR.20 was designed and developed quickly, with the design being finalised in 1935 and the first prototype (serial number M.M.274) flown at Turin on 10 February 1936. Production orders were quickly placed, initial deliveries being made to the Regia Aeronautica in September 1936.