An improved version of the Ca.101, the Ca.133 introduced a number of drag-reducing features, including long-chord engine cow lings, faired undercarriage legs and spatted wheels. The design of the tail unit was also improved. On 6 March 1936, a Ca.133 made the first photo-reconnaissance sortie over the Ethiopian capital, Addis Ababa, in support of Italian operations. Out of 419 Ca.133s produced for the Regia Aeronautica, 329 were Ca.133T transports and 21 Ca.133S ambulance aircraft. During World War II, Ca.133s operated in all theatres of war where Italian forces were engaged, including the USSR.