The ability to determine whether a simulated moving sound source was approaching or receding was measured in several experiments using a 2 alternative, forced-choice task. Three auditory motion cues of intensity changes, Doppler frequency shifts and inter-aural time delays were encoded onto puretone stimuli and presented over headphones. Six subjects were instructed to discriminate simulated approaching versus receding sounds. The cues were presented for several velocities, durations and simulated motion paths parallel to the median-saggital and frontal planes. As found in previous studies (Ryffert et al., 1979; Altman, 1999), approaching sounds encoded with monaural cues of frequency and intensity changes congruent with the frontal and median-saggital planes were detected at slower velocities than receding sounds. Subjects were more sensitive to ITD changes for paths parallel to the median-saggital plane than those parallel to the frontal plane (Mills, 1958; Hartman and Rakerd, 1985; Jenison and Wightman, 1995). Approaching versus receding discrimination thresholds were lower with the combined cues than with the three cues separated. The subjects were able to combine the monaural frequency and intensity changes and binaural inter-aural time delays to improve their judgments of approaching and receding sounds.