The aim of this review was to survey the available literature on prodromal and residual symptoms of panic disorder. Both a computerized (Medline) and a manual search of the literature were performed. In a substantial proportion of patients with panic disorder with agoraphobia a prodromal phase can be identified. Most patients report residual symptoms despite successful treatment. Residual symptoms upon remission have a prognostic value. There appears to be a relationship between residual and prodromal symptomatology (the rollback phenomenon). Appraisal of subclinical symptomatology in panic disorder has important implications as to the pathophysiological model of disease, its conceptualization and treatment.