Two yes-no detection experiments were used to investigate the effects of a contralateral cue on the detection of a brief 20-msec, 500-Hz signal followed by a monotic masking noise. The masking stimulus, a 20 dB increment in an otherwise continuous (41.5 dBA) broadband noise, was presented at various specified time delays (1 ⩽ Δt ⩽ 320 msec) following the observation interval. The signal and cue were narrow bandpass filtered noise bursts in one experiment, and sinusoids in the other. Both signal (p = 0.5) and cue (p = 0.1) were presented during the same observation interval under three different phase conditions: 0°, 180°, and random phase. Relative to the no cue condition, the amount of backward masking found in both experiments under all cue conditions was significantly reduced (∼3–5 dB) at short delays (Δt < 20 msec), and only slightly reduced at longer delays. Under all cue conditions, the reduction in the amount of simultaneous masking and the reduction in backward masking at long delays was approximately equivalent. [This research was supported by a grant from NINDS.]