Knee osteoarthritis (OA) affects approximately one third of older adults in the United States. The pain accompanying its progression reduces quality of life and leads to activity restriction and physical disability. Evidence suggests that exercise represents a promising treatment for pain among older knee-OA patients. The article provides an overview of the extant research examining the effectiveness of exercise interventions in reducing pain symptoms among older adults with knee OA. Critical evaluation of the literature reveals that aerobic training, strength training, and combination aerobic and strength training result in improvements in pain. The magnitude of pain reduction accompanying exercise interventions varies considerably across studies, however. In addition, most trials have focused on short-term (<6 months) interventions, and the limited number of long-term (>6 months) trials have been plagued by high attrition and poor postintervention maintenance of treatment effects. Given the variability in the effectiveness of exercise interventions, future research is necessary to determine the individual differences that influence older OA patients' responsiveness to exercise interventions and identify more efficacious strategies for promoting the maintenance of long-term exercise.