An increasing body of data has shown that moderate physical exercise has preventive and therapeutic effects on several clinical and mental disorders,3,12 especially mild to moderate depression.4,13 Although much is already known about the effects of routine exercise on cognitive function, the acute effect of exercise remains to be studied in depth. Diverging results might be partly explained by factors such as the following: the time of assessment (during or after exercise); the type, intensity, and duration of the exercise; and the type of cognitive task under study.14,15 Studies with young subjects have shown that reaction time, attention, and working memory improve after one session of aerobic exercise.16,17 However, little is known about the effect of acute exercise in the elderly with or without psychiatric disorders. Hoffman et al. observed that routine physical exercise did not improve the cognition of depressed elderly.18 Another study examined the effect of acute exercise on the cognition of adults with depression19 and showed that patients improved their attention and inhibi- tory control immediately after an exercise session. To the best of our knowledge, however, there are no studies on combined cognitive and motor tasks in depressed elderly individuals. The present study aimed to assess cognitive performance during and after one session of physical exercise among elderly persons with major depression. We hypothesized that the most complex cognitive functions would worsen during and improve after moderate physical exercise.