The 1930s were the years in which the Alfa Romeo legend took shape. Engine reliability was undisputed and the names of valorous drivers - Antonio Ascari, Gastone Brilli Peri, Giuseppe Campari, Enzo Ferrari, Tazio Nuvolari, Achille Varzi - were on everybody's lips. They won many legendary races: Mille Miglia (11 wins, an undefeated record), Le Mans 24 Hours (four consecutive editions), Targa Florio, and a very long list of international Grand Prix. In addition, the valuable indications arising from racing were transferred to standard production models.
The worldwide recession that followed the Wall Street Crash of 1929 had repercussions on Alfa's expansion: the company was taken over in 1933 by IRI (Istituto per la Ricostruzione Industriale - Industrial Reconstruction Institute). Ugo Gobbato was appointed Managing Director. He rationalised and reorganised production focusing on the core business of aircraft engines, industrial vehicles and touring and racing cars. The company left the world of racing in the year and its "8C2300B" cars were given to Scuderia Ferrari. Results were brilliant: Alfa won more races than any other manufacturer in 1934, and racing even outshone standard production in 1936. Aeronautic production reached nearly 80 percent of the entire yearly revenue. New orders came in, also from abroad, and a new plant was opened in Pomigliano d'Arco (Naples) at the end of the decade.
The outbreak of World War II on 10 June 1940 unsettled the company's ambitious plans. As most Italian industries, Alfa converted to war production and its plants were bombed by the Allies (the Portello plant ceased operations all together following the damage it received on 20 October 1944). Work resumed the following April after the peace treaty was signed but the workshops had been damaged and there were no components for making aircraft engines, coaches or cars. So the eight thousand workers of the Portello plant made electric cooking ranges, metallic furniture, doors, windows and shutters - in other words, the objects needed to rebuild a country.
Auto building was resumed only in 1946. Pre-war 6C 2500s rolled out of the factory and 158s salvaged from the debris raced on tracks. New versions (Freccia d'oro and Villa d'Este), fitting an innovative steering wheel mounted gear shift, soon arrived. The 1900, the first Alfa with monocoque body shell, was designed by Orazio Satta Puliga (who had joined the company in 1938) in 1950, and the first assembly chain was opened at the Portello plant. Racing wins multiplied. The supremacy of the Alfa 158 in Grand Prix was absolute and Nino Farina won the Formula 1 World Championship in 1950. In the following year was legendary Juan Manuel Fangio's turn: he won the second Championship behind the wheel of an Alfa Romeo 159 fitted with the most powerful 1500 engine ever made delivering 425 HP at over 300 km/h. Straight afterwards, Alfa decided to retire from Grand Prix competitions but kept on competing in the Sport category with the "1900 Disco Volante", a flying-saucer shaped car capable of reaching a top speed of 225 km/h. In the meanwhile, the company concentrated on the production of standard cars, industrial vehicles, aircraft and naval engines, and diesel engines for industrial applications. Following the IRI reorganisation in 1948, Alfa passed into the Finmeccanica sub-holding.