Prospective remembering reflects the ability of an individual to form and later realize intentions that must be delayed over minutes, hours, or days. A substantial body of literature, primarily based upon the findings of behavioral studies, indicates that there are robust declines in the efficiency of prospective remembering in later adulthood. However, the cognitive and neural mechanisms mediating age-related deficits in prospective remembering are not well understood. In this review we consider evidence from recent behavioral and electrophysiological studies indicating that decreases in the efficiency of prospective memory in older adults results from age-related differences in those neural mechanisms supporting the encoding of intentions into memory and the detection of prospective memory cues in the environment.