INTRODUCTION: Depression is a heterogeneous illness affecting large numbers of patients with far reaching effects on both psychiatric and medical outcomes as well as quality of life. Knowledge about the different treatment modalities used to treat depression is important to all physicians. AREAS COVERED: This article expands on one such treatment option, mirtazapine. The paper examines this medication's medicinal chemistry, pharmacological properties as well as the efficacy of the medication compared to other commonly used antidepressants. EXPERT OPINION: Mirtazapine is a medication unlike other agents used for depression both in its mechanism of action as well as its side effects. Knowing these distinct characteristics will enable physicians to better utilize this agent for the benefit of their patients.