Attenuation measurements were performed on the quadriceps femoris muscle of 10 normal volunteers. The measurements were made using a statistical narrowband pulse echo method operating at 4.3 MHz. The results show a normal range of 4.71 ± 0.44 dB cm-1 (mean ± S.D.). A one-way analysis of variance was performed on the data which concluded that the populations of attenuation coefficients among the subjects were indeed distinct at the p < 0.0005 level.