OBJECTIVE To report on the prevalence of comorbid migraine in bipolar disorder and the implications for bipolar age of onset, psychiatric comorbidity, illness course, functional outcome, and medical service utilization. BACKGROUND Migraine comorbidity is differentially reported in bipolar versus unipolar depressed clinical samples. The bipolar disorder-migraine association and its consequences have been infrequently reported in epidemiological studies. METHODS Data for this analysis were derived from respondents (n = 36 984) to the Canadian Community Health Survey - Mental Health and Well-Being (CCHS). Respondents reporting a lifetime WHO-CIDI-defined manic episode and physician-diagnosed migraine (lifetime) were compared to respondents without migraine on sociodemography, course of illness, and medical service utilization indices. RESULTS An estimated 2.4% of the sample met criteria for bipolar disorder. Persons with bipolar disorder had a relatively higher prevalence of migraine versus the general population (24.8% vs. 10.3%; P < .05). The sex-specific prevalence of comorbid migraine in bipolar disorder was 14.9% for males and 34.7% for females. Bipolar males with comorbid migraine were more likely to live in a low income household (P < .05); receive welfare and social assistance (P < .05); report an earlier age of onset of bipolar disorder (P < .05); and have a higher lifetime prevalence of comorbid anxiety disorders (P < .05). Bipolar males with comorbid migraine were also more likely to utilize primary (P < .05) and mental health care services (P < .05) . Bipolar females with comorbid migraine had more comorbid medical disorders (P < .05) and were more likely to require help with personal or instrumental activities of daily living when compared to bipolar females without migraine. CONCLUSION Bipolar disorder with comorbid migraine is prevalent and associated with greater dysfunction and medical service utilization, notable in males. Opportunistic screening and surveillance for bipolar and comorbid migraine is warranted.