Acupuncture has been repeatedly reported to relieve pain associated with osteoarthritis of the knee. As the vast majority of information on the effectiveness of acupuncture on this condition is based on data collected in Western countries, little is known about patients with osteoarthritis of the knee in Asian countries. In this pilot clinical study, acupuncture was incorporated into the standard care for adult patients with osteoarthritis of the knee to determine its contribution to pain relief and improved mobility. In a prospective, non-randomized controlled study, patients with osteoarthritis of the knee were separated into two groups. The first (the experimental group; n = 12) was scheduled for up to 8 sessions of acupuncture in addition to standard care, while the second (the control group; n = 12) received standard care only. Measurements using the six-minute walking distance test, pain visual analogue scale, and osteoarthritis of the knee outcome measurement were taken at baseline and after 4 weeks. Both study and control groups showed significant improvement with respect to time effects in terms of six-minute walking distance, pain visual analogue scale, pain domain and mobility domain scores determined by the osteoarthritis of the knee outcome measurement (p < .01), after adjusting for covariables. However, improvements measured in the study group did not differ significantly from those in the control group. Patients with osteoarthritis of the knee seemed to experience clinical improvements in six-minute walking distance, pain relief and mobility when their standard care was supplemented with acupuncture.