Osteoarthritis is the most common form of arthritis and affects up to 37% of adults in the United States. The knee is one of the most commonly affected joints, especially among the elderly; knee osteoarthritis inflicts considerable pain, stiffness and limited range of motion, resulting in morbidity and health services utilization. While conventional treatments provide some relief, they are associated with a number of untoward side- effects, including excess mortality from upper gastrointestinal bleeding. Acupuncture has a long history of safe and effective use for a variety of conditions in Asia, and reports of clinical success in patients with osteoarthritis have appeared in recent years. However, efforts to scientifically evaluate its efficacy have been impeded by a number of methodological problems.The protocol for the present study represents the investigator's concerted attempts to resolve some of these problems. The purpose of this study is to measure and evaluate changes in the valid and reliable outcomes of self-reported pain and physical function among patients age 50 and above with osteoarthritis of the knee. The study will be a single- blind, controlled trial with independent assessments, comparing the effects of traditional acupuncture and conventional therapy. Results of this study will provide important data about the usefulness of acupuncture in this common disabling condition.