Between 1979 and 1990 the Flygvapnet received 149 second-generation JA 37s for the interceptioin role. During 1993-1997 Saab converted 48 AJ 37, 25 SF 37 and 25 SH 37s to AJS 37 standard to provide integrated attack, fighter and reconnaissance capabilities. Funding problems restricted the upgrade and a common standard was not achieved. Despite this programme, the attack/recce Viggens were rapidly replaced by JAS 39 Gripens and only one wing (F21) operated these AJS 37s in 2001.

Meanwhile the JA 37 has been kept continually up-to-date, with the most recent programme referred to as the Mod D standard. This adds an updated PS46A radar and a new weapons interface and stores management computer that enables the use of AIM-120 AMRAAMs. The first upgraded JA 37 was re-delivered in 1998. The JA 37 currently equips four wings, each with two Divisionen (squadrons). Ten of the Flygvapnet's 14 surviving Sk 37 trainers have been converted into SK 37E Stor-Viggens (jammer Viggens). These will be tasked with electronic warfare training for Sweden's armed forces and operational EW support for Flygvapnet combat units as well as type conversion for all future Viggen pilots. Electronic warfare equipment comprises various systems installed in the airframe, as well as advanced U95 active jammer pods, U22/A jammer pods and KB chaff and flare dispenser pods. The Viggens were finally replaced by the Gripens in 2006.