SummaryThe objective of this study is to review research on acupuncture in the treatment of osteoarthritis of the knee, to document adverse effects, and to identify patient parameters associated with outcomes. A literature search was completed using Alt Med., CINAHL, MEDLINE, and the Cochrane database, since 1977, using the key words acupuncture, knee, osteoarthritis, and pain. Studies were excluded that involved electrical stimulation of acupuncture needles, injection therapies, and other knee pathologies including patellar femoral pain, rheumatoid arthritis, and gonarthritic pain. Five trials representing 205 patients with osteoarthritis of the knee were identified. There are rare but mild side effects from acupuncture that include bruising and nausea. The evidence suggests that acupuncture reduces pain in osteoarthritis of the knee. The best results for reducing pain in osteoarthritis of the knee with acupuncture treatments occurs in patients who report the highest pain levels. Preliminary results suggest that long-term continuous treatment with acupuncture sustains the effectiveness in pain reduction. Also, there is sustained pain reduction 4 months after an initial 6-week treatment regimen was discontinued.