The first prototype, the MB 170 AB2-A3 No.01, equipped as a two-seat attack bomber or a three-seat reconnaissance aircraft, made its maiden flight on 15 February 1938. It was powered by two Gnome-Rhône 14N radial engines and was armed with a 20 mm Hispano-Suiza cannon in the nose, two 7.5 mm MAC 1934 machine guns in the wing, with another machine gun flexibly mounted in the rear cockpit, with a ventral cupola housing either a rearward firing machine gun or a camera. The second prototype, the MB 170 B3 No.2 was a three seat bomber, with the ventral cupola removed, a revised canopy and larger tail fins.