To meet demand for numbers, Heinkel constructed a factory at Oranienburg. On 4 May 1936, construction began, and exactly one year later the first He 111 rolled off the production line.The Ministry of Aviation Luftwaffe administration office suggested that Ernst Heinkel lend his name to the factory. The "Ernst Heinkel GmbH" was established with a share capital of 5,000,000 ℛ︁ℳ︁. Heinkel was given a 150,000 ℛ︁ℳ︁ share. The factory itself was built by, and belonged to, the German state. From this production plant, 452 He 111s and 69 Junkers Ju 88s were built in the first year of the war. German production for the Luftwaffe amounted to 808 He 111s by September 1939. According to Heinkel's memoirs, a further 452 were built in 1939, giving a total of 1,260. 1940s production suffered extreme losses during the Battle of Britain, with 756 bombers lost
The He 111's rival – the Ju 88 – had increased production to 1,816 aircraft, some 26 times the number from the previous year.Losses were also considerable the previous year over the Balkans and Eastern Fronts. To compensate, He 111 production was increased to 950 in 1941. In 1942, this increased further to 1,337 He 111s. The Ju 88 production figures were even higher still, exceeding 3,000 in 1942, of which 2,270 were bomber variants. In 1943, He 111 increased to 1,405 aircraft. The Ju 88 still outnumbered it in production as its figures reached 2,160 for 1943.The Allied bomber offensives in 1944 and in particular Big Week failed to stop or damage production at Heinkel. Up until the last quarter of 1944, 756 Heinkel He 111s had been built, while Junkers produced 3,013 Ju 88s, of which 600 were bomber versions.  During 1939–1944, a total of 5,656 Heinkel He 111s were built compared to 9,122 Ju 88s.[73] As the Luftwaffe was on the strategic defensive, bomber production and that of the He 111 was suspended. Production in September 1944, the last production month for the He 111, included 118 bombers. Of these 21 Junkers Ju 87s, 74 Junkers Ju 188s, 3 Junkers Ju 388s and 18 Arado Ar 234s were built. Of the Heinkel variants, zero Heinkel He 177s were produced and just two Heinkel He 111s were built.