The relationship between pediatric anxiety disorders and physical health is not well-understood, but appreciation of the importance of this relationship is growing. Significant functional impairment may accompany a chronic physical health condition such as asthma, diabetes, or epilepsy, and anxiety may complicate the course. In addition, physical disease can present with symptoms of anxiety, and anxiety disorders may present or be associated with physical symptoms such as functional abdominal pain, headache, and fatigue. This article describes anxiety and its association with physical disease, outlines assessment, and presents a treatment overview including psychotherapy and pharmacotherapy.