Officine Meccaniche Reggiane SA began development of a single-seat fighter which was based very closely on the US Seversky Aircraft Corporation's P-35 designed by Alexander Kartveli. Competitive evaluation against the Macchi MC.200 resulted in this latter aircraft being ordered into production for the Regia Aeronautica, although the Reggiane Re.2000 had shown itself to be superior in manoeuvrability, even when flown against the Messerschmitt Bf 109E. The type was ordered by the Hungarian government, which also acquired a manufacturing licence. Re.2000s were supplied also to Sweden, being operated until 1945 by the Flygvapen under the designation J.20. And though rejected by the Regia Aeronautica, the Italian navy acquired 12 Re.2000 Serie II fighters especially strengthened for catapult launching, followed by 24 Re.2000 Serie III aircraft with increased fuel capacity for deployment as long-range fighters.

Installation of the Daimler-Benz DB 601A-1 engine led to the Re.2001 Falco II, first used operationally by the Regia Aeronautica over Malta in 1942. Luftwaffe priorities for DB 601 engines meant that the Re.2001 had to be powered by a licence-built version of this engine, the Alfa Romeo RA.1000 RC 41-la Monsonie, but with the Macchi MC.202 having first call on production of these engines the manufacture of Re.2001s was limited to only 252.