Demand for total joint arthroplasty is projected to increase in the first three decades of the twenty-first century. With increasing frequency, patients who have a hip or knee replacement expect to, and choose to, participate in athletics following rehabilitation. In general, patients who have had a hip or knee replacement decrease their participation in, and intensity of, athletic activity following the total joint arthroplasty. The orthopaedic literature on athletic activity after total joint arthroplasty is limited to small retrospective studies with short-term follow-up. Expert opinion regarding appropriate athletic activity after total joint arthroplasty is available from the Hip Society and the Knee Society. When patients who have undergone joint replacements choose to participate in athletic activity, orthopaedic surgeons should provide information with which to evaluate the risk of sports activity and recommend appropriate athletic activity.