The ability to localize a click train (100-Hz click rate, 300-ms duration, 70 dB SPL) was measured in the presence of a white noise masker, using an array of 11 speakers located in the horizontal plane at azimuth angles ranging from -90 to 90 deg. All clicks were low-pass filtered at 11 kHz. Clicks were low-pass filtered at 1.6 kHz in the low-pass condition and high-pass filtered at 1.6 kHz in the high-pass condition. Six signal-to-noise ratios (S/N) ranging from -9 to 18 dB (plus a silent condition) and three masker locations (-90-, 0-, and 90-deg azimuth) were tested. Results obtained with four normal-hearing listeners show that, in the broadband and high-pass conditions, localization performance is not affected by noise when S/N is greater than 0 dB. Below this value, performance degrades slowly when S/N decreases and when noise is presented straight ahead; performance degrades rapidly when S/N decreases and when noise is presented at the sides. The same pattern of results is observed in the low-pass condition when noise is presented straight ahead. When noise is presented at the side, performance measured with low-pass filtered clicks starts to worsen at higher S/N's and reaches a lower level.