Detailed clinical records were kept on a series of 55 agoraphobic patients who presented to a general hospital psychiatric practice over a 3 year period. A review of the records revealed that 91% of these patients were diagnosed as suffering from a unipolar or bipolar primary affective disorder. The anxiety and phobic symptoms tended to mask the presence of the affective disorder. This observation is consistent with most of the published data on the agoraphobic syndrome. It could also explain the inconsistent effects of treatment of agoraphobia compared with simple phobias. The possible biological and psychological connections between primary affective disorders and the agoraphobic syndrome are discussed.