Functional abdominal pain (FAP) is a common pediatric disorder associated with impairment in functioning that may persist for the long term. Anxiety is common in youth with FAP, and may be an important factor in predicting youth who are at greatest risk for increased impairment because of pain symptoms. In this article, we examine the relation between anxiety and impairment in youth with FAP. Furthermore, we explore various biopsychosocial factors (eg, neurobiological substrates, coping strategies, social factors) that may be implicated in the relation among FAP, anxiety, and increased impairment. Finally, we propose physician guidelines for screening and treatment of youth with FAP and co-occurring anxiety. Youth with FAP and co-occurring anxiety may benefit from cognitive-behavioral therapy in the context of multidisciplinary care. Copyright © 2013 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.