Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are common treatments for osteoarthritis (OA) with good-to-excellent outcomes. As the US population ages, rates of OA and THA/TKA will continue to rise. People with OA and THA/TKA are less active than those without arthritis or arthrosplasty, respectively. With the numerous documented health benefits obtained from physical activity, it is imperative from a public health perspective that patients are sufficiently active to maintain health after surgery. Increasing moderate-intensity physical activity is a safe, efficacious, and cost-effective mechanism for improving health and reducing health care costs in this population. The return to leisure/sporting activities after THA/TKA is not as well studied as other aspects of functional recovery. In particular, no evidence-based guidelines for physical activity after THA/TKA are available. Most recommendations have been derived from cross-sectional surveys of orthopedic surgeons. Based on the literature, the general consensus for recommendations appears to be to: 1) return to low- to moderate-intensity activities and no-, low-, or intermediate-impact activities within 3 to 6 months postoperatively, 2) discourage high-impact activities, 3) avoid high-contact athletic activities, and 4) educate rather than dissuade patients from resuming leisure/sporting activities. Sports medicine physicians are in an ideal position to counsel patients in regard to leading active lifestyles. The physician can evaluate and treat any remaining functional limitations postoperatively, as well as prescribe the appropriate dose (ie, type, intensity, frequency, and duration) of physical activity. The 2008 Physical Activity Guidelines for Americans can help guide physicians in prescribing the appropriate dose of activity. Finally, physicians can refer patients to evidence-based, community-delivered group exercise and/or behavioral change interventions that are approved by the Centers for Disease Control and Prevention for people with arthritis.