The rifle was developed in the late 1980s in response to a requirement to replace the 7.62mm RK 62 service rifle. Between 1988 and 1990, the SAKO company developed the M90 prototype, which was a substantially upgraded variant of the RK 62. Changes to the original design included the fire control and safety selector, whose lever was transferred to the left side of the receiver housing, the cocking handle cut-out in the bolt carrier assembly was covered with a strip of metal.