This article examines a model of illness as a stressor that activates an individual's characteristic attachment behaviors. These behaviors are the result of the attachment system, a mammalian trait that exists in order to maximize the odds of survival of an infant born without the necessary maturation for immediate independence. Attachment concepts, such as attachment style, coherence, and reflective functioning, are briefly explained, followed by examples of their application to the psychological management of patients with medical or surgical illness. Attachment theory provides a unique, simple, and pragmatically useful model for understanding the particular ways that individuals can feel and react when stressed by illness, and how the professional may help manage that distress.