The efficacy of acupuncture as an adjunctive therapy to pharmacological treatment of chronic pain due to knee osteoarthritis was studied with a 3-armed, single-blind, randomized, sham-controlled trial; it compared acupuncture combined with pharmacological treatment, sham acupuncture including pharmacological treatment, and pharmacological treatment alone. A total of 120 patients with knee osteoarthritis were randomly allocated to 3 groups: group I was treated with acupuncture and etoricoxib, group II with sham acupuncture and etoricoxib, and group III with etoricoxib. The primary efficacy variable was the Western Ontario and McMaster Universities (WOMAC) index and its subscales at the end of treatment at week 8. Secondary efficacy variables included the WOMAC index at the end of weeks 4 and 12, a visual analogue scale (VAS) at the end of weeks 4, 8, and 12, and the Short Form 36 version 2 (SF-36v2) health survey at the end of week 8. An algometer was used to determine changes in a predetermined unique fixed trigger point for every patient at the end of weeks 4, 8, and 12. Group I exhibited statistically significant improvements in primary and secondary outcome measures, except for Short Form mental component, compared with the other treatment groups. We conclude that acupuncture with etoricoxib is more effective than sham acupuncture with etoricoxib, or etoricoxib alone for the treatment of knee osteoarthritis.