A number of techniques with different degrees of accuracies have been devised for the measurement of acoustic wave attenuation in solids and liquids. Still, a wide variation is observed in the attenuation values in different materials reported in the literature. Present numerical study based on a 'propagating wave' model analysis clearly shows that the attenuation constant obtained from exponential fitting of the echo heights in pulse-echo method differs from the exact value of intrinsic attenuation in the medium, even in the ideal situation of plane wave propagation without diffraction, dispersion or scattering.Keywords: Pulse-echo technique, Attenuation measurement, Propagating wave model.Since the discovery of piezoelectric transducers, Pulse-echo method [1] has become the most popular experimental technique for the determination of acoustic velocity and attenuation in solids and liquids. Accurate measurement of attenuation becomes difficult due to reasons like diffraction, scattering and divergence of the ultrasonic beam. Efforts have been given to estimate relevant correction factors [1] and technical development as well [2][3][4]. Still, the common experience is that, though velocity values obtained are in good agreement with each other, attenuation values show wide variation and deviates much from theoretical calculations. To be specific, we consider the data available in the literature for pure water [2,3,[5][6][7][8]. These are presented in Table-1. A recent work by R Martinez et. al. [7] reports a comparison between the through-transmission and pulse-echo techniques for measuring attenuation in tri-distilled water at 25 o C and 19.8 o C. They observed high variation in the value of α measured at short distances from the transducer whereas at long distances measurements in the two methods produce comparable data but, the value differs widely from other reported values. Secondly, their result shows higher wave amplitude for pulse-echo method at far zone and attenuation value obtained from through transmission method is found to be a little higher than that obtained by pulse-echo method. P K Dubey et. al.[3] developed a high resolution technique based on very accurate measurement of echo amplitudes in pulse-echo set up and obtained a value for attenuation in distilled water at 34 o C comparable to the result reported by J M M Pinkerton [5]. In this communication we present a 'propagating-wave ' model approach [9] to analyze the pulse-echo response and from numerical calculation we show that the attenuation constant (α m ) obtained from an exponential fitting of the observed echo amplitudes deviates from the exponential decay constant (α) of the freely propagating wave.