A piston for an internal combustion engine comprises a crown, a skirt section extending from the crown, and an oil ring groove. The piston further comprises a drain hole and a cooling channel. The drain hole extends from the oil ring groove to an inside space of the piston. The cooling channel is formed in the crown at a level above the oil ring groove, and arranged to covey a cooling oil. The cooling channel includes a channel segment which is located near the drain hole and which is formed to have a sectional shape avoiding the drain hole.