A large proportion of obsessive-compulsive disorder (OCD) patients are refractory to pharmacological and cognitive-behavioral therapy. The aim of this pilot, waitlist-controlled trial was to evaluate the effectiveness of electroacupuncture (EA) as add-on therapy for treatment-resistant OCD. Nineteen patients with treatment-resistant OCD were assigned to EA treatment for 12 sessions (5 sessions per week, n = 10) or waitlist for controls (n = 9) while continuing their current anti-OCD medications. The clinical outcomes were measured using the Yale-Brown Obsessive-Compulsive Scale and the Clinical Global Impression-Severity at baseline and end point. EA additional treatment produced significantly greater improvements at end point compared with the waitlist group in reducing both Yale-Brown Obsessive-Compulsive Scale (10.2 +/- 4.2 vs. 18.8 +/- 7.4, p = 0.004) and Clinical Global Impression-Severity scores (3.0 +/- 1.1 vs. 4.4 +/- 1.1, p = 0.002). As an additional therapy, EA is effective in alleviating OCD symptoms of treatment-resistant patients. A large-scale controlled study is warranted.