Persistent medically unexplained symptoms (MUS) are a serious problem because they are common, difficult to treat effectively, and have a significant impact on both functional outcomes and health-care utilization costs. An attachment-existential formulation of psychological factors that are associated with persistent MUS is presented, based on the interaction of death anxiety and preoccupied (anxious) attachment. Psychotherapeutic treatment recommendations that follow from this formulation are described in the form of a brief psychotherapy, involving semi-structured weekly sessions and narrative-writing homework that explores attachment and existential themes. This is the first description of a brief psychotherapy that integrates attachment theory and existential psychology.