This study was a randomized, double blind, controlled trial to evaluate electroacupuncture (EA) as a treatment for back pain in sport horses. Objective measurements of pain threshold levels were obtained with a pressure algometer. Twenty three horses with chronic back pain were divided into control (N=7) and treatment (N=16) groups. Trigger (painful) points were identified on each horse and baseline pain threshold measurements were taken. There was no significant difference (p= 0.386) between the initial pain threshold measurements for the control and treatment groups. The control group received sham EA treatments with no needle penetration or electrical stimulation. Routine EA was performed in the treatment group using filiform acupuncture needles inserted into GV-20, GV-6 and bilaterally at BL-26, BL-54, BL-21 and BL-17 connected to 5 pairs of electrical wires and an electronic acupunctoscope with a current of 4.5 volts. An electrical impulse was delivered at a frequency of 20 Hz for 15 minutes and 80-120 Hz for 15 minutes. Both sham and control EA treatments were given every 3 days for 5 times and all horses were rested during the study period. After 5 treatments, pressure induced pain was significantly reduced at the trigger points in the treatment group as compared to the control group using an unpaired t-test (p=0.034). The conclusion was that EA and rest is an effective treatment for sport horses with chronic back pain and is better than sham EA and rest over a 15 day period.