A one-dimensional mathematical model that predicts the attenuation characteristics of the muffler reversing section has been developed. The model is based on the generalized four-pole-analogy of the propagation of acoustic plane waves in two-in-parallel tubing configuration. Transmission loss measure-ments using the two microphone random excitation technique- were carried out on four different samples of the muffler reversing section. Comparison between measured values of the transmission loss and those predicted by the mathematical model demonstrate a reasonably good overall agreement. However, shifts of the calculated transmission loss peaks at some frequencies reflect slight deviation between theory and experiment. Closer agreement between theoretical and experimental results can be obtained by developing a more complicated three dimensional model.