This study investigated the effects of age on two parameters of auditory temporal processing: auditory duration discrimination and the backward interference of auditory duration discrimination. Young and elderly listeners with normal hearing sensitivity participated. In experiment I, the just-noticeable difference (JND) in duration between a standard 1000-Hz tone of 40 msec and a comparison tone of longer duration was evaluated using a three-interval forced-choice task. In experiment II, the duration discrimination paradigm was presented with a tonal masker following the tonal stimulus at three delay times: 80 msec, 240 msec, and 720 msec. Age effects were observed on the duration discrimination task with interference but not on the initial duration discrimination task without interference. These results suggest that the time required to process the duration characteristics of acoustic stimuli is prolonged in elderly listeners.