It has been 17 years since the latest edition of Diagnostic and Statistical Manual of Mental Disorders, DSM-IV, was published. While it was recognized for utilizing empirically-based literature reviews, establishing reliability of the criteria via field trials, and introducing the clinical significance criterion, DSM-IV has weaknesses that may have hindered research advancement and patient diagnostic assessments. Plans to address these shortcomings in the fifth edition of DSM (DSM-5) began with a systematic review of the state of the science and identification of the most significant research gaps in psychiatric diagnosis and nosology. The result was a collection of white paper publications, which led to a collaboration between the American Psychiatric Association, the World Health Organization, and the National Institutes of Health to convene a series of diagnosis-specific research planning conferences. The DSM-5 Task Force and Work Group members were then convened and charged with developing a clinically useful DSM-5 based on scientifically-sound research evidence. The current DSM-5 revision process is guided by several principles, including prioritizing clinical utility, implementing empirically-driven changes, and making DSM-5 a “living document” that can be readily amended to keep pace with scientific advances in the field. Revision strategies are being developed to harmonize with planning for the 11^th edition of the International Classification of Diseases with the hope of creating a globally unified diagnostic scheme.