Globally, million people suffer from mental illness and available data indicates that the prevalence of bipolar disorder (BPD) in the United States ranges from 3.5% to 6.5%. In the primary care setting, most patients with BPD are in the depressed rather than the manic or hypomanic phase of the illness. Because the depressive episodes in BPD may be indistinguishable from those inthe major depressive disorder, missed diagnosis many occur. Late diagnosis can lead to otherwise avoidable direct and indirect costs to patients, their families, and the health care delivery system. Research reflects high prevalence of missed diagnosis of BPD in the primary care setting, where the majority of initial antidepressant medications are prescibed by primary care providers. Although mania or hypomania is a necessary component for diagnosing patients with BPD, depressive symptoms dominate the course of this illness which makes it challenging for clinicians to make an accurate diagnosis. It is estimated that 6.5% of New Mexico State residents, where the project took place, have severe mental illness, including BPD. Several research findings maintain high prevalence of missed diagnosis in primary care settings, making it essential to diagnose this mental health disorder early and accurately. The purpose of this capstone project was to promote confidence of differential diagnosis BPD in primary care providers by encouraging utilization of a valid and reliable Mood Disorder Questionnaire (MDQ) and by initiating a change in the current culture of repeated missed diagnosis or misdiagnosis of the bipolar disorder spectrum. This capstone project was based on a theoretica question, stemming from years of interviewing and treating patients with BPD in the primary and psychiatric care settings: Can utilization of a simple form (MDQ), promote primary care providers’ confidence in differential diagnosis of BPD in the primary care settings? To accomplish this objective, MDQ forms were utilized by seven different providers at their primary care settings. Methodologies that were instrumental in the accomplishment of this project included the Johns Hopkins Nursing Evidence-Based Practice (JHNEBP) and the Leading Change model by Kotter. Results of retrospective quantitative ratio analysis showed participating provders’ incremental confidence increase in differential diagnosis, treatment, or prompt referral of patients with BPD. The results of this project concur with several research studies conducted previously in utilizing MDQ forms for differential diagnosis of BPD. The outcomes reflected that utilization of the MDQ is instrumental in promoting appropriate treatment of patients with BPD, and the project leader strongly suggests MDQ form utilization as a routine screening instrument for all patients who seek treatment for depression in primary care settings.