Most patients in acute depression trials fail to achieve remission with antidepressant monotherapy. Many patients seem to require more than one medication to achieve remission or adequate response. Augmentation strategies are commonly used in clinical practice, but most have been poorly studied. In addition, better-studied strategies, such as the use of lithium and thyroid augmentation, have not been well investigated in combination with newer antidepressants. Various novel strategies are being investigated as augmenting agents, including selective dopamine agonists, sex steroids, norepinephrine reuptake inhibitors, glucocorticoid-specific agents, and newer anticonvulsants. We review the status of augmentation strategies in the treatment of depression.