One hundred seventy-nine patients with knee osteoarthritis were randomized to NMES (n=90) or sham (n=89). The primary outcome was change in WOMAC pain at 8 weeks. Secondary outcomes included WOMAC stiffness/function/total, Oxford Knee Score, numeric pain ratings (rest/movement), isometric knee extensor strength, shuttle walk tests, swelling, health-related quality of life, sleep, and mood. Outcomes were assessed at baseline and 8 weeks. Overall, the results of the study revealed no between-group difference in the primary outcome, while both groups improved within-group. No clinically important between-group differences were seen across strength, function, or quality-of-life measures. These findings suggest combined quadriceps-plus-calf NMES does not confer additional pain relief over sham in symptomatic knee osteoarthritis over 8 weeks.