We examined the accuracy of the anxiety not otherwise specified (anxiety NOS) diagnosis in 61 patients, using data from older Veterans screened for a large trial of cognitive behavioral therapy for late-life generalized anxiety disorder. We compared the anxiety NOS diagnoses based on the electronic medical record to diagnoses obtained via a gold standard structured diagnostic interview conducted for this trial. We found concordance of the anxiety NOS diagnosis in only 2 participants (3%). Most patients (77%) met diagnostic criteria for a specific Diagnostic & Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) anxiety disorder, including generalized anxiety disorder, posttraumatic stress disorder, panic disorder, and/or social anxiety disorder, on the basis of a structured diagnostic interview. The erroneous diagnosis of anxiety NOS is a barrier to patients receiving appropriate evidence-based care for specific anxiety-related and trauma-related disorders. Undertreated anxiety can result in poorer health outcomes, overutilization of medical services, and increased health care costs. Accurate diagnosis of anxiety disorders is foundational to evidence-based treatment; thus, it is imperative that patients presenting with anxiety symptoms receive proper diagnostic assessment to facilitate access to the appropriate evidence-based mental health services.