OBJECTIVE: To investigate the effects of electrical dry needling (DN) plus corticosteroid injection (CSI) on pain, physical function, and global change in patients with osteoarthritis of the knee (KOA). DESIGN: A prospective, single-blinded, randomized controlled trial. SETTING: Pain treatment clinic. PARTICIPANTS: Sixty patients with KOA were randomly assigned to the electrical dry needling plus corticosteroid injection (electrical-DN+CSI) group or CSI group. INTERVENTIONS: The CSI group received glucocorticoid injection only once during the trial, and the electrical-DN+CSI group received glucocorticoid injection combined with 4 sessions of electrical-DN. MAIN OUTCOMES MEASURES: The primary outcome was the numerical rating scale at 3 months. The secondary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index, the time to complete the Timed Up and Go test, and the score of the global rating of change scale at 3 months. A generalized linear mixed-effects model was used to analyze the repeated measurement data. RESULTS: Baseline characteristics and measurements were similar in the 2 groups. The group by time interaction effect was significant for all variables (P<.05). The electrical-DN+CSI group obtained a more significant reduction in pain intensity and more significant improvement in dysfunction than the CSI group at 3 months (P<.05). The median global rating of change score for the CSI group was +3 (somewhat better), and that for the electrical-DN+CSI group was +4 (moderately better). CONCLUSION: Electrical-DN therapy at myofascial trigger points combined with CSI is more effective at alleviating pain, improving dysfunction, and creating global change than CSI alone for patients with KOA. Electrical-DN may be an essential part of treatment for KOA rehabilitation.