A high-pressure piston pump for feeding fuel to an internal combustion engine, in particular a diesel engine, is provided with a pump housing (2); at least a piston (6) reciprocated in a cylinder (3); a roller (12) for reciprocating the piston (6); and a fuel suction valve (7) to selectively let in low-pressure fuel from a fuel feeding duct (4) in the cylinder (3) and isolate the cylinder (3) from the fuel feeding duct (4) when the piston (6) is in the compression stage; the suction valve (7) having a valve plate (21) and a valve shutter (22), which cyclically impacts on the valve plate (21) and is made of a material selected in the group of the cemented carbides.