Although most social work clinicians probably know the health benefits of physical activity, many may not know how it may be used clinically within the practice context or how to promote it as a therapeutic adjunct. Others may not be fully aware of the tremendous potential psychotherapeutic benefits that may be obtained through physical activity. Perhaps it may be easy for clinicians to say, in effect, Of course physical activity is good for you so 'just do it.' Unfortunately, deference to this popular sneaker company slogan does little to bring about positive change in clients' fitness and health and, consequently, their desired physical and psychological effects. Social workers need to get active in promoting physical activity, and in doing so, they need to collaborate with other fields directly involved in addressing the physical inactivity problem, including physical activity sciences, health psychology, public health, and medicine. The scholarly literature illustrating positive physical and psychological benefits of regular physical activity is growing. Despite this burgeoning knowledge, most people do not maintain a sufficiently active lifestyle (Pratt, Macera, & Blanton, 1999; U.S. Department of Health and Human Services, 1996). Physical inactivity among a large portion of the U.S. population is responsible for rapid increases in medical care costs that will become increasingly more difficult to sustain. Indeed, research has shown that by increasing participation in regular moderate activity levels among the 88 million inactive Americans ages 15 and older, annual medical costs may be reduced by as much as $76.6 billion (Pratt, Macera, W North, McCullagh, & Tran, 1990; Wang & Brown, 2004) and stress reactivity and anxiety (Landers, 1997; Landers & Petruzzello, 1994). On the other hand, being physically active is positively associated with cognitive functioning (Etnier et al., 1997). Regular physical activity enhances well-being and vigor and produces beneficial emotional effects across ages and for both genders. Therefore, it can be an appropriate adjunct to mental health therapy (Fontaine, 2000; International Society of Sport Psychology, 1992). Behavioral medicine researchers are acutely aware of the difficulties in getting people to adopt a physically active lifestyle. Seeking to remedy the problem has led to the proposal of several ecological models that incorporate both internal and external factors that may affect a client's participation (Spence & Lee, 2003). For example, a recent article in the Journal of the American Medical Association suggested that multiple community organizations, agencies, and programs should work together to provide support for client physical activity (Estabrooks, Glasgow, & Dzewaltowski, 2003). This suggestion has important implications for social workers who perhaps are not yet significant players in physical activity promotion efforts. Practitioners, therefore, need to be knowledgeable about the conditions under which increased physical activity may be particularly helpful for clients, and they need the resources to promote physical activity among of their clients. In addition, wherever possible, social workers must align with other professions and organizations to encourage physical activity, fitness, and health if they are to fully promote the total well-being of their clients. PRIMARY CONSIDERATIONS: CLIENT AND CONTEXT Buckworth and Dishman (2002) cautioned that one size does not fit all when attempting to adopt regular exercise behavior. The unique personal characteristics of the client, along with the client's physical and psychosocial contexts, must be carefully considered (Buckworth & Dishman; Estabrooks et al. …