This paper describes the rationale for the new diagnosis of somatic symptom disorder (SSD) within DSM5. SSD represents a consolidation of a number of previously listed diagnoses. It deemphasizes the centrality of medically unexplained symptoms and defines the disorder on the basis of persistent somatic symptoms associated with disproportionate thoughts, feelings, and behaviors related to these symptoms. Data are presented concerning reliability, validity, and prevalence of SSD, as well as tasks for future research, education, and clinical practice.