The 1900 was offered in two door or four door models, with a new 1884 cc (bore 82.55 mm, stroke 88 mm), 90 bhp, 4 cylinder twin cam engine. It was spacious and simple, yet quick and sporty. The slogan Alfa used when selling it was "The family car that wins races", not-so-subtly alluding to the car's success in the Targa Florio, Stella Alpina, and other competitions. In 1951 the short wheelbase 1900C (c for corto (Italian for short) version was introduced. It had a wheelbase of 2,500 mm (98.4 in). In the same year the 1900TI with a more powerful 100 bhp (75 kW; 101 PS) engine was introduced, it had bigger valves, a higher compression ratio and it was equipped with a double carburetor. Two years later the 1900 Super and 1900 TI Super (also 1900 Super Sprint) with 1975 cc engine were introduced (bore increased to 84.5 mm, stroke unchanged). The TI Super had two double carburetors and 115 bhp (86 kW; 117 PS). Transmission was a 4-speed manual on basic versions and 5-speed manual in Super Sprint version, the brakes were drum brakes. The 1900 had independent front suspension (double wishbones, coil springs and hydraulic telescopic shock absorbers) and live rear axle.
Production at the company's Milan plant continued until 1959: a total of 21,304 were built, including 17,390 of the saloons.
The chassis was designed specifically to allow coachbuilders to rebody it, the most notable of which was the Zagato designed, 1900 Super Sprint Coupe, with an improved engine and custom body design. The Alfa Romeo 1900M AR51 (or "Matta") is a four-wheel drive off-road vehicle based on the 1900-series.
Industrias Kaiser Argentina produced between 1960-1962 a car named IKA Bergantin in Argentina, the body and suspension was from 1900 Berlina and engines were from Willys line, 4-L 151 cu in (2.5 L) In. and the 6-L 226 cu in (3.7 L).