The critical masking interval, the time period during which noise is effective in masking a brief click, was measured in two independent experiments. The first paradigm was the temporal analog of Fletcher's critical band experiment. That is, the click was presented in the temporal center of the noise, and its threshold was measured as the masker duration was varied. The second paradigm investigated the temporal analog of Greenwood's [J. Acoust. Soc. Am.33, 484–502 (1961a)] masking experiment; that is, a click was moved temporally through the noise burst. The two paradigms yielded similar numerical estimates of the critical masking interval. Further, the critical masking interval was not greatly affected by the stimulus' bandwidth.