The central auditory system for event perception involves the integrating mechanism of sequential information addressed by the present study. The mismatch negativity (MMN) component of the event-related potentials (ERP) reflects the automatic detection of sound change. ERPs to occasionally omitted stimuli were measured when sequences with constant stimulus onset asynchronies (SOAs) were presented. In separate blocks, the SOA was from 100 to 350 ms. A clear MMN was elicited by a stimulus omission in a sequence of regularly spaced tone pips only when the SOA was shorter than 150 ms, yielding an estimate for the duration of the temporal window of integration used the perceptual segregation of auditory events.