The Bf-109G entered ARR service March 1943. The first unit to be equipped with it was the 7th Fighter Group. This unit had previously flown the Bf-109E and received the new airplanes directly on the front, when it was part of JG 3 Udet. The first mission flown by a Romanian Bf-109G was on 29 March. The first combat casualty occurred the same day, as did the first victory in a Gustav. The Group enjoyed a lot of victories until late October 1943, when it was replaced by the 9th Fighter Group, which took over its airplanes and a part of its most experimented pilots.

Another unit equipped with the Bf-109G was the 53rd Fighter Squadron, which scored 2 confirmed kills on 1 August 1943, during Tidal Wave, for the price of one damaged.

By summer 1944, the 7th Fighter Group was partially re-equipped with Bf-109Gs and joined the 9th Fighter Group in the fights against the VVS and the USAAF. After 23 August 1944, the two groups were brought in to defend the capital against German air raids and shot down a part of the Luftwaffe bombers and transports.

The remnants of the Bf-109G groups formed the 7th/9th Fighter Group, soon renamed 9th Fighter Group and sent on the front in Transylvania. The 44th Fighter Squadron was also sent there. It was a mixed IAR-80/Bf-109G unit. The first engagement between Romanian and German Gustavs took place on 18 September. The Germans prevailed, damaging the airplane of slt. Andrei Pop. The 44th Squadron was retreated in late 1944. The 9th Fighter Group was practically the only Romanian fighter unit on the front, since the IAR-80s of the 2nd Fighter Group were assigned to ground attack. In February 1945, it was joined by the 1st Fighter Group, also equipped with Gustavs. The Romanian Bf-109Gs remained in front line service until the end of the war and even managed to score a kill against a Bf-109K, the last and best model of this legendary airplane.

The majority of Romanian aces achieved their victories with the Gustav. They all spoke very highly of it. Lt. av. Teodor Greceanu (20 victories) once said "it fit him like a glove". Cpt. av. Serbanescu even thought it was better than the Mustang, but, unfortunately, he was proven wrong on 18 August 1944, when he was shot down (and died) by several USAAF P-51s. It was by far the best fighter ARR had during the war and also the most effective. It was the only one to score confirmed kills against the Mustang.

The Bf-109G2

The Bf-109G4

The Bf-109G6