Background: Acupuncture is an attractive treatment option for chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) that has proved refractory to conventional medical treatments. Unfortunately, it is difficult to determine the benefit of acupuncture because few studies have employed controls or had physiological outcome measures. Objective:To determine the feasibility of a sham, or minimally invasive, acupuncture as a control for studies evaluating the efficacy of acupuncture treatment for chronic pelvic pain. Methods: Participants were recruited from a double-blind randomised trial comparing acupuncture with a sham procedure for patients with CP/CPPS. Acupuncture or sham procedures were performed over a 10-week period. Sham acupuncture involved placement of short needles at sites 0.5 cm away from true acupuncture points (CV1, CV4, SP6 and SP9). Participants were asked to determine their procedure allocation at the end of treatment. A total of 35 participants also agreed to have blood analyses for cortisol, β-endorphin and leucine-enkephalin. Results: Thirty-five (78%) of the 45 participants randomised to the sham treatment thought they had received acupuncture compared with 27 (61%) of the 44 participants randomised to acupuncture (p=0.11). Biochemical data showed no differences between the groups immediately after treatment. Thirty-two (73%) of 44 acupuncture participants met the predefined clinical response criterion compared with 21 (47%) of 45 sham acupuncture participants (p=0.017, relative risk 1.81, 95% CI 1.3 to 3.1). At the end of the study, β-endorphin and leucine-enkephalin levels were both higher in the acupuncture group (p<0.01). Conclusions: Minimally penetrating acupuncture was found to be a valid sham control and may prove useful for evaluating the efficacy of acupuncture for other conditions.