The origins of the Cinquecento trace to the early 1980s, with focused research projects of the Consiglio Nazionale delle Ricerche in Rome, studying a super-economical vehicle – from which a series of prototypes evolved, with abbreviations X1/72 to X1/79.

[3] In parallel, FSM, not yet under FIAT's ownership, was studying the BOSMAL, a small car project that would culminate in the concept Beskid 106.

Options included central locking, power windows, sunroof, full-length retractable canvas roof, split rear seat, headlight range adjustment, and air conditioning.

Although the 704 cc engine was mounted longitudinally, the bigger units were fitted transversely, making the little Fiat one of the few cars in the world available with both configurations at the same time.

In order to be fitted in the front-wheel drive Cinquecento, it underwent a major refurbishment (although the engine still employed a carburettor), which resulted, among other changes, in the crankshaft revolving in the opposite direction than in the 126p BIS.

In 1994, Fiat introduced the Cinquecento Sporting, featuring the 1108 cc SOHC FIRE 54 PS (40 kW; 53 hp) engine from the entry level Punto of the same era, mated to a close ratio gearbox.

Other additions were a drop in standard ride height, front anti roll bar, 13" alloy wheels, plus colour coded bumpers and mirrors.

Unlike purpose built electric cars, the Cinquecento Elettra used two battery packs, one in the engine bay and one under the rear seats, replacing the fuel tank.