A double-blind comparative study of clomipramine and fluvoxamine was performed in 50 patients suffering from anxiety disorders (DSM-III). Patients were treated for 6 weeks with either 150 mg of clomipramine or 100 mg of fluvoxamine. The results show that both drugs at the dosages used are equipotent in reducing anxiety symptoms as assessed with the Hamilton Anxiety Scale and the Spielberger State-Trait Anxiety Inventory. Clomipramine differed from fluvoxamine in its efficacy with respect to associated depressive symptomatology in that it had a more pronounced effect on the Self Rating Depression Scale. The results support the hypothesis that brain serotonergic pathways are implicated in the pathophysiology of anxiety disorders, particularly in agoraphobia and panic disorders.