At the time of the Geneva's International motorshow in March 1971, Lamborghini presents a concept car named “LP500”. A mass production of the car was not considered, but the concept likes, so that Lamborghini decides to carry out and release a model resembling to it. However, many details are modified. The 5 liters V12 engine of the prototype LP500 became in 1974, with the LP400, a 4 liters which was going nevertheless to become famous. The name LP means “Longitudionale Posteriore" in reference to the position of the engine.

The name "Countach" comes from an expression of the regional dialect of Emilie-Romagna (It). It marks the expression of astonishment and admiration which would have said by a local farmer, by seeing the car, put on road for the first time.

The car was produced from 1974 to 1978 as Lamborghini Countach LP400. It has a 3.929 cc V12 engine which develops 375 hp. The engine is inserted axially, contrary to the Miura. The gearbox with five speeds was moved in front of the engine, and from there the input shaft crosses the sump to reach the tail rotor drive. Contrary to the monoshell of the Miura, the Countach had a lattice framework, but the body was always signed by Bertone.