The study of comorbidity between bipolar (BPD) and anxiety disorders (AD), and in particular panic/agoraphobic (PD) disorder provides an opportunity to address important clinical and research questions. Epidemiological and clinical studies have documented the high lifetime rates and risks related to BPD comorbidity in PD patients. This comorbidity is associated with several indices of severity such as early onset, mixed presentations, severity of symptoms, poor symptomatic and functional recovery, suicidal behaviour, diminished acute response to pharmacological treatment, decreased quality of life and an unfavourable course and outcome. The identification of the temporal sequence in comorbid BPD and AD may provide a refined view of the association between these comorbid syndromes. Coexisting conditions, whose onset often precedes BPD, may divert the clinicians’ attention from the detection of mood instability, thus diminishing the possibility of early and timely intervention. The empirical basis for therapeutic decisions remains largely inadequate. No firm recommendations can be made as to which mood stabilizer is best for a BPD patient based on his/her particular co-morbid AD. Generally, the available data support the use of valproate as the mood stabilizer of choice for PD patients with comorbid BPD, especially in the presence of prominent anxiety symptoms, mixed features and/or rapid cycling. Antidepressants should be used with caution and in combination with mood stabilizers.