A multiple baseline design across behaviors was used with 8 agoraphobics to evaluate respiratory retraining (RR), in-situ isometric relaxation (I IR), cognitive modification (CM), and a placebo treatment, imaginal rehearsal (IR). As hypothesized, RR significantly reduced psychophysiological accomplements of panic, I IR reduced anxiety, and CM reduced cognitive distress. The placebo treatment IR had a moderate but transitory effect. RR was the most effective component, and also reduced panic frequency, catastrophic cognitions. anticipatory anxiety, and behavioral avoidance. I IR also reduced panic frequency. The combined treatment components produced dramatic reductions in situational avoidance and anxiety, free-floating anxiety, panic frequency, and SCL-90R scores. All behavioral measures improved, as did work adjustment and marital satisfaction. These gains were maintained over the 6-year follow-up; however, 7 partial but temporary relapses occurred. The implications of these relapses for both theory and treatment are discussed, together with the role of exposure and anxiety management.