BACKGROUND: Cognitive decline in the elderly is a subject of intense focus. However, there is a lack of consensus regarding definition of significant decline in connection with repeated testing and the interpretation of cognitive tests results must take into account the practice effect and variability in test performance. The aim of this study was to collect cognitive test results with repeated testing in an elderly healthy population. METHODS: 161 healthy controls =60years were included. Cognitive testing was performed upon entry into the study, at 1week and 3months. Practice effect was evaluated on 7 neuropsychological measures and reference values of clinically important changes were calculated according to z-scores above 1.96. RESULTS: Test scores improved significantly (p