Hypomanic episodes can be seen in both treatment of unipolar or bipolar depression. Bupropion, an inhibitor of dopamine and noradrenalin reuptake, is an antidepressant that modulates dopaminergic systems. Meanwhile bupropion is considered as least risky in mania/hypomania induction. A 29-years-old male patient with the complaints of anergy, anhedonia and sadness is admitted to our clinic. Patient’s history revealed two hypomanic episodes lasting about two months. Patient was diagnosed as Bipolar Depression and he was put on lithium carbonate treatment with the dosage of 900 mg/day. Due to the limited improvement of the patient’s depressive symptoms, bupropion was added. After 5 days, the patient switched to hypomanic state characterized by increased speech, decreased need for sleep, euphoria and increased sexual desire. Antidepressant-induced hypomanic / manic episodes are also considered as bipolar type III. In differential diagnosis of bipolar types, the emergence of symptoms by the initiation of treatment and clinical improvement after cessation of the drug may help to understand the drug induced switches.