The BMD-4M is fitted with a two-man turret armed with a 2A70 100mm caliber gun, coupled to a 30mm 2A72 cannon and a 7.62mm PKT coaxial machine gun mounted to the right of the main armament. The 100mm gun uses an automatic loader with 34 rounds of 100mm ready to fire and 18 in reserve. The main gun can fire conventional types of ammunition and also the 100mm laser-guided ammunition Arkan Tandem 9M117M1 which can be used against modern main battle tanks at a maximum range of 5,500m and against sheltered and exposed personnel and fortifications at a maximum range of 7,000m. Unobserved threats, antitank weapons and other small targets, fixed-wing and rotary-aircraft can be engaged at a maximum range of up to 4,000m. A total of eight Arkan ammunitions are carried, with four ready to use and four in reserve. Three smoke grenade dischargers are mounted to each side in front of the turret. The BMD-4M can fire during day and night, while the vehicle is on the move, stationary, or afloat. The weapon station is equipped with an advanced computerized fire control system including a combined day/night gunner's sight, a commander’s panoramic TV-aimed sight, a digital computer, an automatic target tracker, and automatic devices which supply data on unobserved targets.

The crew consists of a commander, gunner, driver, and six infantrymen. The driver is seated at the front of the hull and has a single-piece hatch cover. There is one more seat on each side of the driver position with one single hatch. The turret is mounted back of the driver position with the commander and gunner. Four infantrymen are seated at the immediate rear of the turret. The engine is at the rear of the hull. The chassis and the turret of the BMD-4M are of all-welded aluminum which provides protection for crew and infantrymen against the firing of ammunition up to 30 mm in caliber on the front and against small arms fire of 7.62mm caliber on the sides.