Background: The ability to remember to complete future intentions, prospective memory, often begins to fail in old age. The aim of the present study was to examine the sensitivity of a computer-based procedure using naturalistic stimuli to age-related increases in forgetting under conditions of high (increased visual and auditory noise) or low distraction. Methods: Participants were tested in a virtual shopping precinct constructed from linked photographs, sounds, and video segments. Groups of 32 older and younger persons completed two concurrent memory tasks while moving along the street. In one task, participants were given errands to complete with an accessible checklist, in the other, they were required to remember to respond to three different targets that appeared repeatedly. Results: The results confirmed previous findings that older adults have difficulty remembering future intentions, even on a self-paced task using naturalistic stimuli, and showed that this was accentuated in noisy environments. Conclusions: Older persons have particular difficulty remembering in noisy environments, and results from testing in the clinic may underestimate the practical memory problems experienced by older adults with mild cognitive impairments. The findings provide encouragement for the construction of computer-generated environments to measure functional deficits in cognition.