Debre Zeyit, as a definite entity, did not come into existence until after the Second World War. Accounts of earlier travelers call the region "Adda", although one Swedish memoir from 1935 mentions a village named "Bishoftu"; the future minister Makonnen Habte-Woldwas born in this village. At about 1 kilometre (0.62 mi) from Adda, on land that had been owned partly by Emperor Haile Selassie I, the Italians started Azienda Agraria di Biscioftu dell'Opera Nazionale per i Combattenti on 15,000 hectares, intending to create a center of colonization as well as an experimental agricultural station. The first foundation stone for the houses was laid 9 December 1937, but only 21 dwellings were ready by May 1938. Various administrative and service buildings were also built.
The history of the Ethiopian airforce is tightly woven with the history of Debre Zeyit. In 1946, the beginnings of what would become the Ethiopian Air Force was moved from the Bole airport in Addis Ababa, which was needed by Ethiopian Airlines, to Bishoftu. The initial group of 19 Swedes under Count Carl Gustaf von Rosen, who were to train the pilots and support personal, arrived there after leaving Sweden between 9 January and 16 July 1946. Both Ethiopian cadets and the Swedish instructors took part in constructing the first buildings on the base. Six Saab 91 Safir training airplanes were bought in Sweden and flown to the new airbase 24 December 1946, and on 10 November 1947 a fleet of 16 Saab-built B-17s were landed at Bishoftu by Swedish pilots.
Debre Zeyit Technical High School was established in 1958 with a 5-year course for boys 12-15 years of age. An Evangelical College had been founded two years before, which was a joint undertaking of Swedish, Norwegian, and German Evangelical missions. The Evangelical College's first headmaster was Sven Rubenson. The Animal Health Assistants Training School was established in Debre Zeyit in 1963, with financial support by the United Nations
