ABSTRACTElectromyographic (EMG) feedback procedures were utilized in treating two adult patients with idiopathic subjective tinnitus. The relationship between behavioral severity ratings of tinnitus and EMG activity at the frontalis muscle was investigated using a single-subject, double-reversal experimental design. Biofeedback procedures were effective in modifying EMG activity levels, but changes in EMG levels were not related systematically to behavioral ratings of tinnitus. It was concluded that the physiologic effects of EMG biofeedback procedures may not be the active ingredient in such treatment procedures.