According to army-technology.com
The M60 is one of the world’s most successful main battle tanks with 15,000 having been produced and serving in the armies of 22 countries. The tank has provided proven battlefield performance over four decades and has been continuously advanced and upgraded with advanced weapon control, ammunition, applique armour and increasingly powerful engines. The M60 series main battle tanks of Egypt, Saudi Arabia and the USA were deployed in Operation Desert Storm in 1991 during the Gulf Crisis.
M60 tanks entered service with the US Army in 1960. The M60A1 with a new turret, thicker armour and a new ammunition stowage system, was manufactured from 1962 to 1980. The development of the M60A2 with a new turret fitted with a 152mm gun and missile launcher was halted and effort was directed to the development and production of the highly successful M60A3, which incorporated improvements to the gun fire control and entered service in 1978.
The manufacturer, General Dynamics Land Systems Division, has ceased production of the tank but continues to provide fleet management support to the US Army Tank Automotive Command and to user countries worldwide.
The US Army phased M60A3 out of service in 1997 and it was superseded by M1 Abrams, a third generation main battle tank.
As of 2010, Egypt is operating around 1,700 upgraded M60A3s while Turkey and Israel are operating 900 and 700 units respectively.