Unaided, many people are notoriously poor recalling and carrying out intentions, prospective memories (PM), that have been delayed by a period of time; an effect that seems to worsen with age. Age effects research in prospective memory, however, have produced conflicting results; some reporting age invariance and others reporting poor performance in older adults. The aim of the experiments reported here was to investigate this debate from the dual perspectives of output monitoring (OM) and executive functions (EF). Output monitoring refers to the evaluative phase of prospective memory processing when a person interrogates memory to determine the status of an intention (e.g. still to do, completed, cancelled, postponed etc.). The principal aim was first to determine whether and when age effects occur in PM and OM and then examine the relationship between PM/OM performance and executive function. The main research consideration was whether, and to what extent is PM performance related to, or influenced by deficits in output monitoring.