It was developed from the Zastava M70 assault rifle, a modified copy of the Soviet AKM, but with a Western type flash eliminator added on the barrel end, chambered in the Western 5.56×45mm NATO caliber, and with a different magazine design, similar to a STANAG magazine.

[2] The M90 was intended to replace the M70 in the Yugoslav Army, but the breakup of Yugoslavia disrupted the production and the weapon today remains rare and was never formally used.

It is gas-operated, air-cooled and magazine-fed, shoulder fired weapon with selective fire capability, and like M70, can launch rifle grenades and has a rifle grenade sight added on the gas tube, instead of under barrel grenade launcher like on most other AK variants.

Like all Zastava-produced AK variants, the M90 can be identified from the originals by its longer lower wooden handguard design, which has three cooling vents, no bulge and like the stock, is made out of different wood type.

Like on the other Zastava AK's, this three-vent feature gives the M90 lower overheating when compared to the originals, but the Western round in this case, slightly reduces reliability.