Abstract: A piston for an internal combustion engine of the type presenting circumferential grooves (10), each groove (10) housing a respective piston ring (20), at least one first upper groove (10) presenting a profile having upper and lower lateral walls (11, 12) radially outwardly inclined towards the piston top by an angle of inclination such as to compensate, at least partially, the deformations to which the piston is submitted when in a critical higher load operational condition, in order to maximize the distribution of the seating contact between at least one of the upper and lower lateral walls (21, 22) of the piston ring (20) and an adjacent lateral wall (11, 12) of the groove (10), as well as to minimize the wear that determines the useful life of the groove (10).