Abstract: A system for quick coupling and uncoupling of a tracked unit with respect to a chassis of a tracked machine, particularly a tracked pipe laying machine, includes at least two supporting structures, configured to be associated with a chassis of a tracked machine. Each one of the two supporting structures includes at least one fixed pin and at least one pin that can move axially along its own longitudinal axis, and at least two coupling devices, configured to be associated with a tracked unit, wherein each coupling device has at least one hook and at least one slot. In a configuration for coupling the tracked unit to the chassis, the hook is mated with the fixed pin and the movable pin is inserted in the slot.