OBJECTIVES Poor continuity of care occurs when patients do not follow-up after being discharged from the hospital. In bipolar disorder problems with continuity of care and medication adherence may lead to expensive relapses. The objectives of this research were threefold: 1) examine the frequency of poor continuity of care for individuals with bipolar disorder; 2) identify the predictors of poor continuity of care; and 3) evaluate the potential increased psychiatric hospitalization costs. METHODS Premier linked their PerspectiveTM Comparative Database (PCD), the largest, most detailed, U.S. hospital database, with the administrative claims from a large managed care organization. We identified 319 individuals who had a primary discharge diagnosis of bipolar disorder in the PCD and who maintained continuous eligibility for the 60 days prior and the 180 days following the hospitalization. Good continuity of care was operationally defined as the presence of a psychiatric visit in the 60 days following discharge. Propensity scores were used to correct for background differences between patients with good continuity of care and patients with poor continuity of care. RESULTS A total of 34.5% of individuals had poor continuity of care. Prior to discharge, individuals who would later have poor continuity of care could be identified. Some variables that independently predicted later poor continuity of care included no psychotherapy visits, no psychiatric visits, substance use diagnoses, and psychiatric hospitalizations. After correcting for background differences, patients with poor continuity of care had reduced mood stabilizer use (94 vs. 116 days, p=0.008) and twice the psychiatric hospitalization charges ($10,027 vs. $4,892, p=0.03). CONCLUSIONS One in three individuals with bipolar disorder did not have a psychiatric follow-up visit after discharge from the hospital. This poor continuity of care appears to lead to decreased medication adherence and increased psychiatric hospitalizations. An effective, targeted intervention could potentially prevent relapses and reduce health care costs.