Bipolar-I disorder (BD-I) is characterized by recurring episodes of mania, depression or mixed episodes without a certain pattern, and patients may have a completely normal mood between these episodes. Endocrinological and cardiovascular disorders in some patients with bipolar disorder may show a common pathophysiological mechanism or metabolic side effects of pharmacotherapy. Diabetes mellitus is among the most important of these disorders, and its frequency among patient population with mood disorders is 3 times higher than the general population Our case was a 52 years old female patient, who is the , first child of a family with 7 children. She is married for 35 years; uneducated, and has a history of meningitis and convulsion when 3 years old. She had Behçet’s disease for 20 years, type 2 diabetes mellitus for 3 years, and metabolic syndrome and hypothyroidism. She was 52 years old, and she was diagnosed as having BD-I when she was 39 years old. After she was first diagnosed as BD-I, she had experienced 14 manic, 3 depressive and 2 mixed episodes, with multiple hospitalizations. She was diagnosed as type 2 diabetes mellitus 3 years ago and was being followed up while taking oral anti diabetic. There were no manic episodes in the first 2 years after DM diagnosis.2000-2011, although she regularly took her psychiatric medications, being hospitalized for 13 times in this period. She passed 2011-2013 period in remission under the control of psychiatric medications, but had 3 manic episodes in 2013 and was treated as an in-patient at our hospital. She also had an episode of hypomania and was treated on an outpatient basis. Her episodes were observed to fulfill the criteria for fast-cycles in the last year. She was hospitalized and treated at our hospital for 3 times in the last year, and her blood glucose regulation was observed to be uncontrolled just before these episodes. Her HbA1c value was 10.2 at hospitalization and level of triglycerides 514 mg/dL. The blood glucose levels returned to 150-200 mg/dL with insulin treatment, and the Young mania rating scale score decreased from 18 points at admission to 2 points. During hospitalization, a rapid decline in her manic symptomatology was observed at the 7th day, in parallel with controlling the blood glucose levels. Her HbA1c level of 10.2 is an important parameter reşecting the level of glucose control of 3 months’ duration. It could not be clearly understood whether this increase in HbA1c was due to her non-compliance, it was due to a side effect of olanzapine disrupting blood glucose control, or to a relationship yet unknown between diabetes and bipolar mood disorder Glucocorticoid / insulin signal mechanisms and immuno-inşammatory effector systems are intersection points, revealing the pathophysiology of the relationship between bipolar disorder and stress-sensitive general medical conditions. Unregulated blood glucose levels during manic episodes and regression of the manic episode with normalization of hyperglycemia, suggests an association of high blood glucose levels with higher frequency and severity of manic episodes in our