After successful operations of the An-24T tactical transport in austere locations, interest in a version with a retractable cargo ramp increased. Initial studies for the retractable ramp were carried out as part of the projected An-40 medium transport. When given the go-ahead for the An-26 in March 1968 the Antonov OKB adapted the ramp design of the An-40 to the An-24 fuselage, thus was born the An-26. Particular attention was given to the military mission and the majority of early An-26 production was delivered to the VTA (voyenno-transportnoy aviatsii).
Using the majority of the An-24 airframe, with its high-set cantilevered wings, twin turboprops and stalky main undercarriage, the An-26 included military equipment, such as tip-up paratroop canvas seats, overhead traveling hoist, bulged observation windows and parachute static line attachment cables. The An-26 made its public debut at the 27th Paris Air Show at Le Bourget where the second prototype, CCCP-26184 (c/n00202), was shown in the static aircraft park.
The An-26 is also manufactured without a license agreement in China by Xian Aircraft Factory as the Y-14, later changed to be included in the Xian Y7 series.
"Curl-A" : Twin-engine tactical transport aircraft.
Convertible passenger/cargo aircraft modified from 'An-26' aircraft at the Kiev plant from 1999.
An arctic surveillance and reconnaissance aircraft retrofitted with the Nel'mo equipment.
(Weather) Another aircraft for weather control duties, similar to the 'An-26 Tsiklon ', with a simplified equipment test lab.
(Flight) A single aircraft retrofitted with the purpose of research of unified air traffic control and monitoring system throughout the USSR, with a comprehensive navigation test lab including precision compasses and Doppler speed/shift sensors.
(Sphere) A single production aircraft built as laboratory for atmospheric research.
(Shtab: or Headquarters) some 'An-26's delivered to the Soviet and DDR air forces for use as staff transports/mobile command posts.
(Life) A single mobile operating room, surgery and intensive care unit ('25 Blue', c/n5406), for the Ukrainian Air Force.
A one-off assault transport prototype with higher performance due to removal of some military equipment.
(Avtomatizeerovannaya Sistema Lyotnovo Kontrolya – automated flight control and monitoring system) : A modern flight control and monitoring system equipped with automatic calibration and navigation system. Recognizable by the distinctive pod low on the forward fuselage side.
A civil cargo version equipped with roller gangs which can be swung up against the cabin walls when not in use. It was also equipped with two ZMDB Progress (Ivchyenko) Al-24VT turboprop power plants to deliver higher thrust.
'Mobile Hospital' : The prototype 'An-26B' retrofitted as a mobile civilian emergency hospital.
(Cyclone) A weather research/control and cloud-seeding aircraft for the Central Aerologic Laboratory. This aircraft was used for rain induction and protection using cloud-seeding chemicals dropped from slab sided pods hung from pylons.
Convertible passenger/cargo aircraft modified from 'An-26B' aircraft at the Kiev plant from 1999.
Alternative designation of the 'An-26RL' Arctic surveillance and reconnaissance aircraft.
(Dal'niy – long-range) An extended range version with extra fuel in wing tanks and additional external tanks attached to the airframe of the fuselage. One aircraft ('21 Yellow', c/n 13806) was retrofitted and delivered, but no further orders were forthcoming.
(Great Auk) A single An-26 aircraft converted to a Kaira test airframe for the development of airborne LASER guided systems.
(Drop [of liquid]) After completion of the LASER designator trials the 'An-26K Kaira' was retrofitted to search or optically guided weapons as the navigation systems. During a night test flight at low-level, in March 1989, the An-26K Kaplya suffered a massive bird strike, which consequently destroyed the windshield and injured the pilot, who involuntarily downed the aircraft into the Azov Sea.
(Kontrol'no-Poverochnaya Apparatura – Testing and calibration equipment) : A navigation aids inspecting aircraft with comprehensive navigation equipment and calibration equipment.
(Letayuschaya Laboratoriya – Protivolodochnoy Oborony – ASW (Anti-Submarine Warfare) testbed) : A single 'An-26A' aircraft, (c/n 0901), retrofitted and modified to accommodate range of sophisticated laboratory for surveillance systems, detecting and tracking stealthy nuclear submarines.
Fire-fighting version, for delivery of field equipment and para-dropping fire-fighters in lieu of water-bombing (any more info?).
(rescue worker) Flying hospital with an emergency surgery facility and consultation conference room.
(Protivopozharnyy – fire-fighting) : Aircraft fire engine fighter, retrofitted with water lifting vessels in pods either side of the lower fuselage.
(Projector or Searchlight) A single conversion of an An-26 as a guided missile system airframe.
(RadioElektronnoye Protivodeystviye – ECM (Electronic Counter-Measures) [aircraft]) : Electronic Counter-Measures aircraft fitted with active jammers in cylindrical pods on either side of the lower fuselage sides, as well as chaff and I/R flares for self-defense.
(Razvedchik Ledovyy – An arctic surveillance, reconnaissance and monitoring) : An arctic surveillance, reconnaissance and monitoring aircraft used to monitor the icebergs and ice formations at arctic circle fitted with SLAR (Sideways Looking Airborne Radar) in long pods on either side of the lower fuselage, extra fuel in a cargo hold fuel tank, provision for surveyors and radar operators.
Alternative unit designation of the 'An-26RT' ELINT(ELectronic INTelligence) aircraft.
"Curl-B": (First use of the designation) A basic designation for a series of ELINT aircraft fitted with a wide range of electro-magnetic surveillance equipment. At least one aircraft, (tactical code '152'), retrofitted with the Tarahn (Ramming Attack) ELINT suite for use in Afghanistan.
(ReTranslyator – Interpreter -Translator): (Substitute of designation) Battlefield communications relay aircraft, fitted with powerful Inzheer (Fig) radio relay system, for connecting forward units to headquarters units.
Alternative unit designation of the 'An-26RT' ELINT aircraft.
(Salon – [VIP] Lounge) : A new VIP Lounge aircraft for the Ukrainian Ministry of Defense delivered about 1997.
(Shturmanskiy – Navigator) : Navigator trainer for the VVS, 36 built at Kiev.
1992 Germany. On 27 February, a German Air Force An-26 "52+10" crashed after a hard landing. None of the crew members was injured.
1992 Libya. Yasir Arafat's An-26 crashed on 8 April 1992 during a sandstorm. Of the 13 on board, both pilots and an engineer were killed.
1995 Angola. On 16 January an Angolan Air Force An-26 was downed by rebel forces in the north of the country, killing all six occupants.
1995 December India. On 17 December, terrorist Kim Davy alias Niels Holck from Denmark dropped several tonnes of lethal weapons, ammunition, explosives and triggers by An-26 in Purulia district of West Bengal State of India. The plane was forced to land in Bombay, where his accomplices were arrested.
The 2007 Balad aircraft crash was a 9 January 2007 airplane incident involving an Antonov An-26 airliner, which crashed while attempting to land at the U.S. military base in Balad, Iraq. The crash killed 34 passengers on board and left one critically injured.
2008 Vietnam. On 8 April 2008 an An-26 crashed during a training mission near Hanoi, killing five Vietnamese military pilots.
2010 Exin's An-26B registered SP-FDO made an emergency landing on the Lake Ülemiste on 18 March 2010, close to Lennart Meri Tallinn Airport. None of the 6 crew members was injured. Initial reports indicated failure of one of the turboprop power plants.
2010 Exin's ANn26B registered SP-FDP rejected takeoff from Tallinn's runway 08 at high speed when the gear collapsed or retracted during the takeoff roll on 25 August 2010. The airplane skidded to a stop on its belly, no injuries occurred.
2011 Gabon. On 6 June 2011, a Solenta Aviation An-26 freighter flying for DHL Aviation crashed in the sea near Libreville, Gabon. Four people on board were rescued and transported to a local hospital, but were not seriously injured.
2012 Sudan. On 19 August 2012, an An-26-100 flying for Alfa Airlines crashed on its second approach to the Talodi airfield in South Kordofan, Sudan. All 26 passengers on board and six crew members died.
2014 Tunisia. On 21 February 2014, a Libyan military An-26, used for medical transportation, crashed in a farm near Grombalia, 60 km short of Tunis-Carthage Airport, after one of its engines caught fire. The accident resulted in the death of all its 11 passengers: 6 crew members, 2 doctors and 3 patients.
2014 Ukraine. On 14 July 2014, a Ukrainian military An-26 transport aircraft flying at 21,000 feet (6,400 m) was shot down. (confirmed to be shot using Buk missile system). U.S. officials would later say evidence suggested the aircraft had been fired on from inside Russian territory 
An-26, tail number "1602" is exhibited in the Polish Army Museum in Warsaw. The inside of the aircraft is open to visitors on Wednesdays, Saturdays and Sundays from 10 a.m. to 3 p.m. and on special occasions.