In the past several years, there has been an increased appreciation for the importance of including cultural and ethnic factors in the evaluation and treatment of patients in psychiatry. Most of the focus has been on understanding the patients' psychosocial milieu and how these factors contribute to the patient's overall clinical presentation. Few studies have addressed the significance of pharmacogenetic heterogeneity among various cultural, ethnic, and racial groups. This article reviews the pharmacogenetic data and summarizes the sparse pharmacokinetic and pharmacodynamic data that pertain to the treatment of mood disorders in different ethnic and racial groups.