A suction muffler for a refrigeration compressor, comprising a hollow body (10) defining at least one dampening chamber (13, 14) that carries a gas inlet duct (20) and a gas outlet duct (30) presenting an inlet opening (21,31) and an outlet opening (22, 32), for communicating the interior ant the exterior of the dampening chamber (13, 14), at least one of the gas inlet and gas outlet ducts (20, 30) presenting at least one closed end (23, 33), one of the inlet and outlet openings (21, 22, 31, 32) being positioned at a certain distance from said closed end (23, 33), smaller than the distance of said opening in relation to the other opening of the same duct (20, 30) and in a region of the latter presenting a minimum acoustic pressure for a determined frequency, the dimensioning of said duct (20, 30) and of the cross section of the first of said openings (21, 31; 22, 32) being achieved so as to minimize the gas pulsation noises inside the suction muffler.