In 1985 the Swedish government decided to modify 54 J 35F2s to J 35J standard. In 1987, 12 more modifications were ordered. Between 1987 and 1991, the aircraft were given a longer lifespan, more modern electronics, a modernized cannon, an additional two Sidewinder (AIM-9L) pylons under the air intakes and increased fuel capacity. The final operative J 35J flew for the last time in 1999.