Acupuncture is a popular complementary treatment for osteoarthritis. In order to define its effectiveness, a systematic review of the literature was undertaken. Independent literature searches identified eleven studies of acupuncture for osteoarthritis. Their results are highly contradictory. Most trials suffer from methodological flaws. The most rigorous studies suggest that acupuncture is not superior to sham-needling in reducing pain of osteoarthritis: both alleviate symptoms to roughly the same degree. This could either mean sham-needling has similar specific effects as acupuncture or that both methods are associated with considerable non-specific effects. Future research should clarify which explanation applies.