The rifle is manufactured by FN America, a subsidiary of FN Herstal SA, a Belgian
firearms company that has been in business since 1889. FN is one of the largest small
arms manufacturers in the world, producing rifles and machine guns for the militaries of the United States and many other countries.

The FN P90 submachine gun was a project that began circa 1990. It was, at the time,
the latest attempt to create what has come to be known as a personal defense weapon.
The idea was to design a compact weapon for military support personnel, something
that would be more useful in a firefight than a pistol but handier than a rifle. As the
theory went, such a weapon would be issued to tankers, truck drivers, artillerymen,
EOD, etc, in lieu of a full-length infantry rifle.

This is not a new idea. The same line of thinking led to the M1 Carbine in World War 2, the experimental Colt SCAMP machine pistol in the 1970s, and even the current M4 carbine. Where the M1 and M4 carbines are conventional in layout, and the SCAMP was a select-fire pistol, the P90 was intended to be an extremely compact weapon that could still be fired from the shoulder.