Abstract: This review examines the role of exercise and physical activity for preventing weight gain in older people. A structured search using MeSH-vocabulary and Title/Abstract-searches was conducted in PubMed for January 2000 to June 2011, identifying weight gain and exercise or physical activity as study topics, and aged adults as target group. In study selection, all types of exercise and physical activity and any measure of weight change in aged adults (≥65 years) or postmenopausal women were considered. N=9 primary studies were identified. All were conducted in the US, with one study additionally including samples from Canada and the UK. Three studies focused on aged adults, while six concentrated specifically on postmenopausal women. Forms of exercise or physical activity comprised self-reported exercise history in four studies and low, moderate or high intensity exercise interventions in five studies. Four studies combined exercise with a hypocaloric diet and included comparison groups receiving either diet only, health education, stretching or a delayed intervention (one study each). Exercise was associated with weight loss (1.1–6kg) in all intervention studies, all of which studied an overweight sample, and with weight maintenance in most observational studies, all of which studied a general population or otherwise overweight-unspecific sample. In sum, exercise and physical activity can effectively prevent weight gain in older adults and postmenopausal women either in terms of weight loss or maintenance. They can preserve lean body mass and thus are important for the balance between potentially positive and negative effects of weight reduction in later life. In addition, since all intervention studies were conducted with an overweight sample, it seems that primordial prevention (in terms of preventing the development of risk factors such as excess weight in the first place) might be a neglected issue in geriatric and postmenopausal prevention.