This study investigated the effect of traumatic brain injury (TBI) on time-, event-, and activity-based prospective memory using a laboratory paradigm developed in the literature on ageing (Einstein, McDaniel, Richardson, Guynn, & Cunfer, 1995). The participants were 12 individuals with severe long-term TBI and 12 community controls. Participants were asked to answer general-knowledge questions on a computer for two sessions. The time- and event-based tasks were embedded in this filler activity. Participants were also required to carry out activity-based actions at the end of the two sessions. Participants with TBI performed significantly worse than did controls on all three prospective-memory tasks, indicating that TBI affects not only retrospective but also prospective memory. Implications of these results for the assessment and rehabilitation of memory problems in individuals with TBI are discussed.