It was Kwiatkowski's plan of reorganization and modernization of Polish arms industry that eventually led to the creation of PZInż, but also the Państwowe Wytwórnie Uzbrojenia (National Arms Works), Państwowe Zakłady Lotnicze (modern PZL), Państwowe Zakłady Optyczne (National Optical Works) and National Factory of Gunpowder and Explosives in Pionki.

On 21 September 1932 the National Engineering Works signed a license agreement with Italian automobile manufacturer Fiat.

Until September 1939, some 10,000 models were produced in Warsaw’s Factory of Passenger and Light Commercial Vehicles (Fabryka Samochodow Osobowych i Polciezarowych).

In 1933, the PZInz was restructured, and divided into the following units: Among vehicles produced by the National Engineering Works, are such models, as: As well as vehicles PZInż also produced aero-engines under licence to various foreign manufacturers, such as: The National Engineering Works also had several prototypes, which did not enter production due to invasion of Poland by Nazi Germany and the Soviet Union.

Shortly after the outbreak of World War II and the German occupation of Poland, the PZInż was confiscated by the German state, its factories dismantled and sent to Germany while a large part of the engineers were either killed or sent to Germany as slave workers.