Because bipolar disorder carries a high risk of relapse and development of chronic affective disorder, long-term maintenance treatment is essential and generally indicated for patients with bipolar disorder. The main goals of maintenance treatment are to prevent clinically significant episodes, to maintain complete remission without subsyndromal symptoms between episodes, and to prevent suicidal acts. Maintenance treatment is multidimensional and includes, for example, most importantly, psychotherapy and psychoeducation, but pharmacotherapy remains the mainstay of treatment. Lithium is the first-line (“gold standard”) medication for the maintenance treatment of bipolar disorder with serum lithium levels ideally in the range of 0.6–0.8 mmol/L. Clinicians should be aware of the narrow therapeutic index (risk of intoxication) and the risk of developing chronic renal dysfunction with long-term lithium treatment. Alternative medications are available for patients who do not respond adequately to or cannot tolerate lithium, including the anticonvulsants valproate, lamotrigine, and carbamazepine/oxcarbazepine, as well as second-generation antipsychotics.