The main focus of this study was to examine age-related changes in self-evaluation of cognitive functioning in the domains of memory, attention, mental speed, planning, and decision making. Almost 2,000 persons in the age range 24 to 86 years rated their present cognitive functioning relative to three different reference points: compared to their age-mates, to their level 5 to 10 years ago, and to their level when they were 25 years. An age-stratified group of 420 participants also completed a series of cognitive tests. Age-related decline in subjective cognitive functioning started at the age of 50 and steadily increased afterward. This decline was not restricted to memory, but also involved changes in attention, mental speed, planning and decision making. When participants compared their present cognitive functioning with that of their own age-group, no age effects were found. Subjective health and depression were both related to subjective decline in cognitive functioning. No relation was found between subjective and objective cognitive functioning. © 2000 Taylor and Francis Group, LLC.