An oil pump for a reciprocating hermetic compressor comprising a pump body, having a free end immersed in the oil, and an opposite end coupled to the compressor, so as to be driven by the latter in a reciprocating axial movement, said pump body defining at the free end thereof a valve seat, and further lodging a sealing means, which is displaced between a closing position, seated on said valve seat, and an opening position, spaced from said valve seat, said positions resulting from the displacements of approximation and spacing of the pump body in relation to the sealing means therewithin.