The literature on the use of biofeedback and various forms of relaxation training in the treatment of psychophysiological disorders was reviewed; special attention was devoted to studies in which biofeedback and some form of relaxation training were compared. Based on this review, we conclude that there is no consistent advantage for one form of treatment over the other with any psychophysiological disorder for which a comparison has been made, e.g., essential hypertension, migraine headaches, premature ventricular contractions, tension headaches, temporomandibular joint pain, asthma, primary dysmenorrhea, and functional diarrhea. For other disorders in which no comparisons have been made (e.g., Raynaud's disease, sinus tachycardia, peptic uclers, and fecal incontinence) biofeedback seems to be a very promising treatment modality.