Kolodny, Masters, and Johnson coined the term sexual medicine in their well-known Textbook of Sexual Medicine .Sexual medicine is the branch of medicine that focuses on the evaluation and treatment of sexual disorders, which have a high prevalence rate. Approximately 43% of women and 31% of men are affected by these disorders .Today the feld of sexual medicine continues to evolve. There have been recent changes in classifcation of disorders, advancements in pharmaceutical management, and improvement in behavioral therapies. This introductory chapter provides a concise review of relevant topics to sexual medicine including recent classifcation changes in the International Classifcation of Diseases, 10th edition (ICD-10) and Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5).