With the success of the Beneš-Mráz Be-50 Beta-Minor Beneš decided to produce a smaller version with better performance for sport flying. A major incentive was the availability of five spare 105abbr=onNaNabbr=on Walter Junior engines, which would imbue the Be-150 with much improved vertical performance compared to the Be-50.
Beneš shortened the fuselage and fitted the short-span wings of the Be-52, retaining the open cockpits and fixed, trousered, tailwheel undercarriage of the Be-50.
The Be-150 was first flown on 5 January 1937, but was rejected by the MNO (Czechoslovak Ministry of Defense) and the three production aircraft were used for general flying club use and for air racing.