A refrigeration compressor having a gas discharge system comprising: a cylinder crankcase defining a cylinder which is closed, at one end, by a valve plate provided with at least one discharge orifice and defining, with the cylinder, one compression chamber; a cylinder cap having a gas outlet and being seated against the valve plate in opposition to the compression chamber and in whose interior is defined a discharge chamber, the valve plate being operationally associated with at least one discharge valve, and further comprising an accelerating means secured to at least one of the parts of cylinder cap and valve plate, in order to receive the entire flow of refrigerant gas released by the discharge valve through the discharge orifice, characterized in that the accelerating means is mounted in the interior of the discharge chamber and defined by a tubular conduct which projects to the interior of the discharge chamber, from the discharge orifice of the valve plate, and comprising a base end wall seated against the valve plate and provided with an inlet nozzle comprising a base opening, open to the discharge orifice of the valve plate and communicating said discharge orifice with the discharge chamber, said tubular conduct being incorporated, in a single piece, to the base end wall and defining an extension of the inlet nozzle to the interior of the discharge chamber, said accelerator means accelerating said refrigerant gas flow, and said tubular conduct being dimensioned to produce the desired acceleration in the refrigerant gas flow released by the discharge orifice, from the moment the discharge valve opens. a cylinder crankcase defining a cylinder which is closed, at one end, by a valve plate provided with at least one discharge orifice and defining, with the cylinder, one compression chamber; a cylinder cap having a gas outlet and being seated against the valve plate in opposition to the compression chamber and in whose interior is defined a discharge chamber, the valve plate being operationally associated with at least one discharge valve, and further comprising an accelerating means secured to at least one of the parts of cylinder cap and valve plate, in order to receive the entire flow of refrigerant gas released by the discharge valve through the discharge orifice, characterized in that the accelerating means is mounted in the interior of the discharge chamber and defined by a tubular conduct which projects to the interior of the discharge chamber, from the discharge orifice of the valve plate, and comprising a base end wall seated against the valve plate and provided with an inlet nozzle comprising a base opening, open to the discharge orifice of the valve plate and communicating said discharge orifice with the discharge chamber, said tubular conduct being incorporated, in a single piece, to the base end wall and defining an extension of the inlet nozzle to the interior of the discharge chamber, said accelerator means accelerating said refrigerant gas flow, and said tubular conduct being dimensioned to produce the desired acceleration in the refrigerant gas flow released by the discharge orifice, from the moment the discharge valve opens.