The Merkava is the main battle tank in service with the Israeli armed forces. The first Merkava Mk 1 tanks were supplied to the Israeli Defence Forces (IDF) in 1979. Production of the Mk 1 continued up to 1983, when the IDF began to receive the Merkava Mk 2. The Mk 2 featured improved mobility, fire control system and armour, as well as the inclusion of an internal 60 mm mortar. Production of Mk 2 continued until 1990 when it was superseded by the Mk 3.

The Merkava Mk 3 entered service with the IDF at the beginning of 1990. All systems and assemblies were of new design and all, except for the engine, are of Israeli design and production. Among the prominent features of the Merkava Mk 3 are: new suspension system, 1200 horsepower engine and new transmission, higher power main gun and ballistic protection provided by special armour modules. About 1000 Merkava Mk 2 and Mk 3 tanks are in service with the IDF.

Development of the Merkava Mk 4 has begun and will include a new compressed gas recoil system and thermal sleeve for the 120 mm gun, to enable the firing of enhanced kinetic energy ammunition.

The main gun is a 120 mm smoothbore gun developed by Israeli Military Industries. The gun has a Vidco Industries thermal sleeve, which increases accuracy by preventing distortion through the effects of heat and shock. The tank carries an ammunition store of 50 rounds of 120 mm ammunition. The tank is also equipped with three 7.62 mm machine guns, two roof mounted and one co-axial with the main gun. The tank carries a store of 10,000 rounds of 7.62 mm ammunition.

The Soltam 60 mm mortar system is capable of firing high explosive rounds and illumination bombs. The crew can load, aim and fire the mortar system from within the turret.

The tank's is fitted with the Amcoram LWS-2 laser warning system, with threat warning display installed at the commander's station.

The turret and the hull are fitted with a modular armour system which can be changed in the field. The forward section of the turret is fitted with additional blocks of armour which provide extra protection against the latest generation of top attack anti-tank missiles.

A skirt of chains with ball weights is installed on the lower half of the turret bustle. Incoming HEAT projectiles detonate on impact with the chains instead of penetrating the turret ring. Sprung armour side skirts protect the wheels and tracks.

The electro-hydraulic turret control system installed on the Merkava Mk 1 and Mk 2 has been replaced by a totally electrical and electronic system in the Mk 3, operated by either the gunner or the commander. The Knight Mk III advanced fire control system, from Electro Optics Industries (EL-OP) and Elbit Ltd, provides the tank with the ability to engage moving targets while on the move.

The gunner's station is equipped with a thermal sight and day television channel, which are stabilised in two axes. A laser rangefinder and target tracker are integrated into the gunner's sight. The Elbit automatic target tracker is able to automatically aim at the target using the image data presented on the day or night sights.

The commander's station is fitted with a sight which can be optically relayed to the gunner's sight. The Merkava 3 is being fitted with a new day/night stabilised panoramic sight, giving hunter/killer capacity.

The Merkava Mk 3 is equipped with an AVDS-1790-9AR diesel supplied by Teledyne Continental Motors. The air-cooled diesel provides 1,200 horsepower, compared to the 900 horsepower engine installed in the Mk 1 and Mk 2. The tank's transmission system was developed by the Ashot Ashkelon Industries Limited subsidiary of Israel Military Industries.