The first British aircraft were delivered in late 1941 to equip Operational Training Units. The RAF only used the Baltimores operationally in the Mediterranean theater and North Africa.
Many users were impressed by the step up that the Baltimore represented from older aircraft like the Bristol Blenheim. The users of the Baltimore, and Martin pilot Benjamin R. Wallace, praised the aircraft for its heavy armament, structural strength, maneuverability, bombing accuracy, and relatively high performance, but crews complained of cramped conditions similar to those in the earlier Maryland bomber. Due to the narrow fuselage it was nearly impossible for crew members to change positions during flight if wounded (the structure of the interior meant that the pilot and observer were separated from the wireless operator and rear gunner). This was common for most light bombers of the era like the Handley Page Hampden, Douglas Boston, and Blenheim. Crews also complained about the difficulties in handling the aircraft on the ground. On takeoff, the pilot had to co-ordinate the throttles perfectly to avoid a nose-over, or worse.
Thrown into action to stop Rommel's advance, the Baltimore suffered massive losses when it was utilized as a low-level attack aircraft, especially in the chaos of the desert war where most missions went unescorted. However, operating at medium altitude with fighter escorts, the Baltimore had a very low loss rate, with the majority of losses coming from operational accidents.
Undertaking a variety of missions in the Middle East, Mediterranean and European theaters, the Baltimore's roles included reconnaissance, target-towing, maritime patrol, night intruder and even served as highly uncomfortable fast transports. The Baltimore saw limited Fleet Air Arm service with aircraft transferred from the RAF in the Mediterranean to equip a squadron in 1944. Used in the anti-submarine role during the war, the Baltimore achieved moderate success, sinking up to eight U-boats.
The RAF also transferred aircraft to other Allies in the Mediterranean area. After the capitulation of Italy in 1943, the type was used intensively in the Italian campaign to clear the road to Rome for advancing Allied forces. After the armistice, an Italian-manned squadron, the 28th Bomber Wing, was equipped with ex-RAF Baltimores, becoming the co-belligerent Stormo Baltimore. The Italians suffered considerable attrition during their training phase on the Baltimore. The majority of accidents were during takeoffs and landings due to the aircraft's fairly high wing loading, high approach speed and a directional stability problems during takeoffs. The Italians only operated the Baltimore for roughly six months. Many of those operations were in Yugoslavia and Greece, providing air support for partisan forces or dropping supplies.
Most Baltimores were scrapped soon after the war, although one RAF squadron continued to use the type in Kenya where the aircraft were used in aerial mapping and locust control until 1948. In post-war service, the Baltimore took part in United States Navy instrument and control surface tests in the effort to break the sound barrier. With its powerful engines and light, yet robust construction, the aircraft was able to be dived at high speed, reaching Mach .74 in tests. All Baltimores were withdrawn from service by the end of 1949, the last one being retired on 23 December 1949.