For older adults, physical activity (PA) plays a central role in the prevention and management of chronic disease, and has the potential to reduce physical decline, maintain functional ability and prevent injuries. This review provides an update of the evidence relating to the effectiveness of PA intervention studies (both general PA and trials specific to progressive resistance training (PRT)) for older adults. The following electronic databases were searched for articles published since 1999: Medline, PubMed, EMBASE, CINAHL and Sport Discus. For the PRT section, a 2002 Cochrane review was also used. Eight general PA intervention studies were included in this review, ranging from one-on-one counselling in general practice to the community-wide promotion of walking. The aim of most of the trials was to increase moderate and/or vigorous activity levels. Most of the studies reviewed had some degree of success in getting older people to be more active. However, a major limitation was the use of self-report measures of PA. The review of PRT interventions included 21 trials. Participants in half the studies had either functional limitations or a chronic condition. Most trials were conducted in a supervised setting using specialised equipment. Increased strength and improvement in basic functional tasks were generally reported, but there was a paucity of strong evidence linking PRT with reduced physical disability and improved health-related quality of life. While considerable progress is being made in this area, further population-based studies that include home and whole-community interventions are required.