Objective: Patients with bipolar disorder are vulnerable to developing metabolic illnesses such as hypertension, dyslipidemia, and type 2 diabetes mellitus. In addition, mood stabilizers, anticonvulsants, and antipsychotic medications, which are commonly used to treat bipolar disorder, have been linked to risk for adverse metabolic changes. This study uses a large insurance claims database to examine the prevalence and costs of metabolic conditions among patients with a bipolar diagnosis relative to a matched non-bipolar sample. Methods: A retrospective analysis was conducted of medical service and prescription claims from the Thomson Health care MarketScan® Commercial Database (includes claims information on more than 12 million employees with employer-based insurance and their dependents in the United States). Claims data for 28,531 patients with bipolar disorder were compared over one year with data for 85,593 age and gender 1-3: matched control patients with no mental health disorders and no psychotropic medication use. The prevalence and health care costs of metabolic conditions in bipolar patients were compared with those of their matched controls. Results: The bipolar cohort had significantly higher overall medical service and prescription drug costs than the control cohort ($12,764 versus $3,140, p<0.0001). Bipolar patients had a significantly higher prevalence of metabolic co-morbidities than the general population (37% versus 30%, p<0.0001), and medical service treatment costs for metabolic conditions were twice that of the control cohort ($531 versus $233, p<0.0001). Prescription medication costs for metabolic conditions were higher as well, with bipolar cohort per-patient costs of $571 versus $301 for the control cohort (p<0.0001). Conclusion: Bipolar patients have significantly more metabolic co-morbidities and higher medical costs than in age- and gender-matched controls. To reduce the medical and economic burden of bipolar disorder, strategies should be identified to prevent the development of metabolic co-morbidities and improve medication adherence.