Abstract: A piston for a heat engine has a chamber adjacent the piston head, for receiving cooling oil for cooling parts of the piston that in operation are subjected to elevated thermal stress. An oil inlet and an oil outlet provide for a suitable flow of oil into and out of the chamber, to ensure controlled cooling of the piston in particular of the piston head surface and the piston ring area. The chamber can be of annular shape so that the central part of the head surface remains uncooled.The invention is particularly suitable for a composite-structure piston.