The RO57 was one of the many attempts made in 1930's through the 1940's by the Italian engineers to supply the Regia Aeronautica with a modern heavy fighter, suitable to support (and even substitute) the slow and old Fiat CR32, CR42 and G50. Giovanni Galasso was however obliged to opt for a twin-engined aircraft, given the usual incapacity of the Italian motor industry to produce engines powerful enough. In May 1939, on the occasion of the First International Aeronautical Journalists' Congress held in Rome (Guidonia), the prototype was analyzed by a group of Italian and foreign pilots, who appreciated its qualities. The RO57 displayed itself better, in almost all the performances, than Macchi MC200 (the best national single-engine fighter), but shown soon a fault in the weaponry (only two 12.7 mm Breda Safat).
The Command of Regia Aeronautica started the production in series of the RO57, as they thought that a twin-engined fighter should definitely have better performances than a single-engined one, being the latter also cheaper in costs and easier to equip. The RO57 looked much like the English fighter Westland Whirlwind (propelled by a couple of 880 hp engines), but more powerful being armed with four 20 mm guns. In 1941. IMAM proposed a new version (Bis) armed with two 20 mm guns and designed to carry a 500 kg bomb, but the aircraft was too heavy. Yet, the Regia Aeronautica ordered 90 units for dive bombing. In February 1943, the first aircrafts were deployed to the Rome-Ciampino-based 97o Gruppo Autonomo. The pilots disliked the airplanes and the new aircraft was not employed in any further mission. At the beginning of July all the RO57s were moved to Crotone (southern Italy), where on July 13th 10 out of 15 aircrafts where destroyed by American air bombing, putting an end to this model's second-rate career.
