Bipolar disorders affect a significant part of the population and a difficult disorder to treat. It is important to diagnose bipolar disorder correctly. Differential diagnosis can include schizoaffective disorder, substance induced mood disorder, mood secondary to medical disorder, or personality disorder. Mood stabilizers are a major treatment modality in bipolar disorder. This paper discusses the use of lithium, divalproex, carbamazepine, and lamotrigine. This paper also reviews the side effects pertaining to these drugs.