[citation needed] Originally developed as a civilian airliner and successor to the Ca.101, the Ca.133 prototype first flew in December 1934, and production began in 1935.

It had a welded steel-tube structure, mixed construction, with metal and fabric covering, main wheel spats, flaps and modified tail surfaces.

The aircraft was powered by three engines, one in the nose, and one under each wing mounted in faired nacelles, with NACA cowlings, supported by steel tubes.

[2] Bomber aircraft operated as military transports, redesignated Ca 133T, had their interiors modified to accommodate 18 fully equipped soldiers.

While in Ethiopia they were widely used, in Spain the Ca.133 was found to be too slow, and highly vulnerable to enemy Polikarpov I-15 and I-16 aircraft, also to heavy anti-aircraft fire.

[citation needed] In mainland Italy, the Ca.133 was used mostly as a light transport aircraft supporting fighter and bomber squadrons by carrying supplies, personnel and spare parts.

[citation needed] The Regia Aeronautica soon realized that despite its improvements, the type was suitable for combat in North and East Africa.

[7] On 12 June 1940, in the south region, three Ca.133s of 66ª Squadriglia from Yavello attacked an Allied column of half a dozen trucks and 200 men.

That night, ten Caproni Ca.133s bombed the port of Aden and Khormaksar airfield, already attacked during daylight hours by seven SM.81s of 29° Gruppo.