Axis IV, one of the five dimensions of clinical description, has provided a way to report psychosocial and environmental problems that may affect the diagnosis, treatment, and/or prognosis of a psychiatric disorder. Originally conceived in DSM-III as a way to rate and rank the severity of particular environmental stressors, axis IV was simplified for DSM-IV to a more straightforward listing of psychosocial factors, given the reliability and validity problems with quantifying the etiologic contribution of specific stresses to mental disorder. In the newest manual, however (DSM-5), the entire multiaxial system has been quietly eliminated. How and why multiaxial assessment was abandoned, and what this implies for social work theory and practice, are addressed in a conceptual review that traces the history and empirical evidence, positive and negative, for incorporating a psychosocial dimension into the diagnosis of mental disorder.