The Cisitalia company was established in Turin in 1946 by industrialist Piero Dusio and racing driver/engineer Piero Taruffi. The two hired Dante Giacosa to design and build a Fiat-based car, with a 1100cc engine. The resulting D46 proved to be very successful and popular in the immediate post-war years. The D46 made its debut in Turin in September 1946 and Dusio won the first race with Louis Chiron third in a similar car. Later that year Tazio Nuvolari took one of the cars to second place in Mantua.
In 1947 Taruffi won the small cylinder class in the Italian Championship driving one of the cars and Felice Bonetto also scored several victories with cars appearing in the hands of Achille Varzi, George Abecassis and many others. There was also a Cisitalia sportscars which raced with some success. Dusio finished second in a race at Belluna and Nuvolari teamed up with Carena to finish second on the Mille Miglia. On the Targa Florio there was another second place for Taruffi and his partner Rabbia. That year Dusio also hosted an all-Cisitalia race in the Gezira Park in Cairo, Egypt, with Cortese beating Alberto Ascari and Taruffi.
That year Dusio was approached by Porsche's Italian distributor Carlo Abarth - who was running a Cisitalia for Scuderia Scagliarini - and asked if he would like to build a Formula 1 design which had been drawn by Ferdinand Porsche. Dusio jumped at the chance but the Type 360 was a complicated car with a 1500cc flat 12 engine which needed development. The car appeared in 1948 but was rarely raced although the D46s continued to enjoy much success in Italy. In 1949 Cisitalia ran into problems with money and at the end of the year Dusio closed down the factory and handed over the sportscar programs to Abarth Corse and moved to Argentina, taking the Grand Prix car with him. This was raced as an Autocar in local races but without much success.
D46s continued to appear in F2 races in 1950 with Abarth fitting some of his own engines into the cars but the competition from Ferrari, Simca-Gordini and HWM was intense. The cars continued to appear at odd races in 1951 and 1952 - when the World Championship was run to F2 regulations. Old Cisitalias continued to appear in various Italian series well into the mid-1950s.