Abstract: A muffler for a motor vehicle is made up of a housing enclosing a pair of sheet metal plates impressed with semi-circular depressions with the plates combining to form a sinuously shaped gas duct of circular cross section. Walls positioned within the housing divide its interior into chambers. Perforations in the gas duct open into the chambers. Lugs are punched out of the sheet metal plates in a uniform pattern and the lugs in one plate are inserted through the corresponding punched openings in the other and are bent into locking engagement with the other plate. These lugs and the corresponding openings contribute to the mechanical strength of the muffler. The ends of the plates forming the inlet and outlet ends for the gas duct have flanges which also contribute to the mechanical strength of the muffler. Cooperating interfitting corrugations in the plates located at specific positions relative to the gas duct prevent partial short circuiting of the exhaust gas flow through the muffler.