AbstractGeriatric clinicians have observed that some demented individuals show increased agitation, restlessness and confusion in late afternoon, evening or night. This has popularly been named ‘sundowning’, or the ‘sundowning syndrome’. References to ‘sundowning’ in clinical writings disagree on virtually every aspect of the syndrome, and little research has been conducted to investigate this phenomenon.In this study, agitation was measured in terms of motor activity, using an electronic monitor with a movement sensor. A total of 12 demented Alzheimer's patients were continuously monitored for four days each. Analyses indicated that some subjects showed increased afternoon activity, but these individuals did not correspond to nursing‐assigned groups of ‘sundowners’ and ‘non‐sundowners’. Movement correlates of ‘sundowning’ were seen in Alzheimer's patients presumably in the mid‐stages of the dementia, and less so in patien