Although age-related multisensory integration has been investigated previously, the effects of aging on multisensory integration elicited by peripherally presented audiovisual (AV) stimuli remain unclear. In this study, visual, auditory, and AV stimuli were randomly presented to the left or the right of the central fixation point; during this time, participants (young and old adults) were asked to respond promptly to target stimuli. Using a race model to analyze the response times, our results showed that the AV behavioral facilitation of young participants was significant (P<0.05), with response times ranging from 240 to 450 ms and peaking at 360 ms (14%). However, the AV behavioral facilitation of elderly participants was delayed and showed an extensive range, with response times ranging from 260 to 540 ms and with a lower peak (12.6%) and delay time (390 ms). We found that the time window of AV behavioral facilitation in elderly participants was longer but more delayed than that in the young participants when the AV stimuli were presented peripherally. This finding also further confirmed that peripheral resolution decreased with age.