Abstract Background Comorbid anxiety disorders and a history of childhood maltreatment are important determinants of outcome in bipolar disorder, but the relationship between these two factors is unclear. Methods In 174 outpatients with bipolar disorder, we assessed history of childhood maltreatment with the Childhood Trauma Questionnaire (CTQ) and lifetime diagnosis of anxiety disorders with the M.I.N.I. International Neuropsychiatric Interview. We used ordinary logistic regressions to test associations between childhood maltreatment and the number of comorbid anxiety disorders, controlling for age, sex and the type of bipolar disorder. Results Ninety (51.7%) participants had no anxiety disorder, 50 (28.7%) had one anxiety disorder and 34 (19.5%) had two or more anxiety disorders. Childhood maltreatment, indexed by a higher CTQ total score, was associated with more lifetime anxiety disorders (OR=1.5; 95% CI=1.01 to 2.14; p =0.04). Of the CTQ subscales, emotional abuse (OR=1.68; 95% CI=1.13 to 2.49; p =0.01) and physical abuse (OR=1.43; 95% CI=1.02 to 2.01; p =0.04) were associated with anxiety disorders. Of the anxiety disorders, panic disorder was most strongly associated with childhood maltreatment (OR=2.27; 95% CI=1.28 to 4.02; p =0.01). Limitations The study is limited by a moderate sample size and the retrospective assessment of childhood maltreatment. Conclusions Exposure to maltreatment in childhood is associated with comorbid anxiety disorders among individuals living with bipolar disorder. Bipolar disorder with comorbid anxiety may constitute a separate aetiological type with a greater contribution of early environment.