Their small surface gave the Bf-109 its excellent climbing capabilities and was more adequate for high speeds, but was also one of its weaknesses : small surface gave high wing loading , which meant the 109 would never be able to turn as tightly as other planes and handling qualities would suffer at low speeds. To solve this problem, advanced high-lift devices were added, as well as automatically opening slats on the leading edge, and fairly large split flaps on the trailing edge. Still, it was clear that maneuvrability would suffer, but since it came last on RLM's list of demands, BFW thought it wouldn't be much of a problem.

The first prototype, designated as V1, was ready in September 1935, and was sent first to Luftwaffe's Test Center at Rechlin for acceptance trials. Having passed all tests, it arrived in March 1936 at Travemünde for the head-to-head contest with its three rivals : the Arado Ar-80, the Focke Wulf Fw-159 and the Heinkel He-112. But the only real contest was between the He-112 and the Bf-109, since the Ar-80 and the Fw-159 were clearly far below Luftwaffe's demands ( the Ar-80 didn't even had a retractible landing gear ! ). Initially, when both planes ( Bf-109 and He-112 ) were powered by Rolls Royce Kestrel VI engines, they seemed to be evenly matched, with a plus for the He-112, who had better maneuvrability and much better cockpit visibility. However, when the new Junkers Jumo engines arrived, the 109's superior streamlining and lower drag gave it a clear speed advantage over its rival. When the RLM found out that the British Spitfire had been ordered into production, a sort of panic set in. As the RLM was keen to put into production any design good enough to match the Spitfire, the contest was declared over with the Bf-109's victory, and a first production serie, the Bf-109A was supposed to start immediately. Armament however was considered too weak, so a few more versions ( B,C, and D ) were built before the Luftwaffe was finally satisfied with the E series : two ( or three ) MG/FF 20 mm canons and two MG17 machine guns. All versions were powered by Daimler Benz DB 601 engines, generating around 1200 HP. The Bf-109E was the first version produced in large numbers and the first one to see service with the ARR.

In April 1939, a Romanian delegation had visited the German aircraft manufacturers and had tried to purchase some Bf-109. For the moment they had to settle for 30 He-112B's, but were promised that as soon as the Luftwaffe would have enough 109's, Romania would be allowed to buy them for its own use. The moment came in December 1939, when an order for 50 Bf-109E's could be placed with BFW. Only 11 planes arrived by the spring of 1940, and the ARR had to wait for one more year until the rest finally came.

The 7th fighter group was equipped with the Bf-109E's ( they had E3's, E4's as well as E7's ) and fought with great success throughout the Bassarabian campaign. Right on the first day of hostilities, three Bf-109E7's from the 57th Fighter Squadron strafed the Soviet airfield at Ialoveni, destroying 5 planes on the ground. Another major victory came on the 9th of July, when the group flew 42 sorties and managed to shoot down 6 Soviet planes without any losses. But the group's finest moment came on the 18th of August, when the Romanian Bf-109E's clashed with I-16 fighters on two occasions, claiming 9 confirmed kills for a single damaged plane. By the end of 1941, the 7th Fighter Group had shot down 62 confirmed VVS aircraft and destroyed 7 more on the ground, for the losss of just six Bf-109's. Lieutenant Nicolae Polizu of the 57th Fighter Squadron, was the highest scoring ace of the 1941 campaign, with 8 confirmed kills.

In early 1942, 15 more Bf-109E7's were purchased in order to replace losses and bring the 7th Fighter Group back to full strength. The group took part in the unfortunate Stalingrad campaign, and had to make a dramatic escape from their airfield near Karpovka, after repulsing Soviet tanks for two days ( somehow, pilots and mechanics managed to squeeze into the 'Emils'-even three men in one plane! ). Those who had escaped merged with the 5th Bomber Group and remained on the front until February 1943, when they were sent home. Surviving Bf-109E's were either used as fighter trainers or given to the 52nd squadron, who flew patrols over the Black Sea. In 1944, the 109E's saw action again as the 52nd engaged a few times the American bombers of the 15th USAF. After the 23rd of August 1944, all Bf-109E's were pulled out of action and finally scrapped in 1946.