Founded in 1946 near Turin by Giorgio Sargiotti, Monterosa began as a carrozzeria producing special bodies. Their earliest examples were mainly estate cars, including those based on the Fiat 1100, in 1949 and the Lancia Aurelia, in 1953.
The desire to produce their cars led to the Monterosa 600, based on the Fiat 600, which was offered in three versions, a 2+2 Sport Coupé (also available with Abarth and Stanguellini engines), a standard saloon and a Lusso saloon with large amounts of chrome. Production was undertaken from around 1959 to 1961.
Other offerings included an estate based on 1100 in 1958 and a lightly retouched Appia in the same year. 1959 saw an unusually styled Fiat 1800 Cabriolet, while one of the last proposals was for a Fiat 1500 Coupé in 1960. The company closed in 1961.