Prompted by the Mars Microphone aboard the 1998 Mars Polar Lander, a theoretical study of the acoustical environment of the Martian surface has been made to ascertain how the propagation of sound is attenuated under such conditions and to predict what sounds may be detectable by a microphone. Viscous and thermal relaxation (termed classical absorption), molecular relaxation, and geometric attenuation are considered. Classical absorption is stronger under Martian conditions resulting in sounds in the audible frequencies (20 Hz to 20 kHz) being more strongly attenuated than in the terrestrial environment. The higher frequencies (>3000 Hz) will be severely attenuated as the absorption is frequency dependent. At very low infrasound frequencies (i.e.,