Integration time is an important feature for perceptual efficiency. An increase in the integration period can reduce perceptual acuity, but a decrease in the integration period can reduce perceptual sensitivity resulting in perceptual deficits. In older people, decreased auditory acuity may contribute to problems in speech and music perception. The mismatch negativity (MMN), an event-related potential (ERPs) component, is a useful tool for assessing the duration of perceptual integration. We compared groups of older and younger participants in two experiments. In the first experiment an omission paradigm was used. When a stimulus within the temporal window of integration was omitted, MMN-like activity emerged. The longest SOA for which we were able to identify an MMN appeared to be longer for the elderly (150-200 ms for the younger and 250-300 ms for the older group, respectively). In the second experiment, two consecutive deviants were presented within the sequences of standards. Duration of perceptual integration is defined as the shortest SOA where the second deviant elicits an MMN. Like the first experiment, results indicated a longer duration period for the elderly.