Up to half of all patients with bipolar affective disorder (BP), develop a comorbid anxiety disorder during their lifetime. The consequences of comorbid anxiety in BP compared to BP without comorbid anxiety are serious, including more frequent and severe depressions and twice the risk of substance abuse and suicide attempts. In this review we argue, that due to the poorer prognosis of these conditions, it is important to diagnose comorbid anxiety when present, and to ensure proper treatment, which should be performed by a psychiatrist preferably specialised in affective disorders.