The goal of our research is to identify individual differences in pediatric functional abdominal pain (FAP) that predict differential health outcomes and can be used to develop tailored approaches to the evaluation and treatment of FAP. Effective treatment of FAP is a critical public health issue because it is among the most common pain problems during childhood and prospectively predicts risk for chronic pain, disability, and frequent health service utilization (HSU) in early adulthood. Although cognitive behavior therapy (CBT) delivered by highly trained professionals in face-to-face sessions has been found to reduce pain in some FAP patients, such intensive resources are not generally available to the large population of FAP patients. This study will evaluate an alternative, more efficient approach to treating pediatric FAP. The study builds on and integrates recent work by two leading investigators in pediatric pain. First, in a prospective natural history study of pediatric onset FAP patients followed into late adolescence/early adulthood, PI Walker and colleagues identified three distinct patient profiles (i.e., Low Pain Adaptive, High Pain Adaptive, High Pain Dysfunctional) comprised of pain severity, pain cognitions, and affect at the time of the initial FAP evaluation in childhood. These profiles predicted chronic pain and related health outcomes at follow-up (FU) nearly a decade later. Patients with the High Pain Dysfunctional profile at baseline had the poorest symptom outcomes and also exhibited pro-nociceptive central pain modulation in laboratory pain testing at FU. The heterogeneity of the FAP pain profile groups suggests that they may differ in treatment needs and in the extent to which they benefit significantly more from adjunctive behavioral treatment as compared to usual care alone. Second, Co-Investigator Palermo developed and tested a CBT intervention delivered online (Web-based Management of Adolescent Pain; Web-MAP) which is an efficient, easily disseminated treatment that significantly reduced pain and disability in youth with a variety of chronic pain diagnoses in comparison to youth randomized to a usual care, wait-list control group. This study merges these lines of research into an innovative study that will, for the first time: (Aim 1) evaluate the efficacy of WebMAP administered to FAP patients and their parents; (Aim 2) evaluate baseline moderators of treatment response, including our previously validated FAP pain profiles, pro-nociceptive central pain modulation, and parent characteristics (protectiveness, modeling pain behavior, catastrophizing about the child's pain); and (Aim 3) evaluate potential mediators of the effect of WebMAP on health outcomes. Pediatric patients (n = 300) ages 11-17 years will be randomized to either WebMAP or a Usual Care (UC) control group following their initial subspecialty FAP evaluation. Assessments will be at baseline, mid- and post-treatment, and at 6- and 12-months post baseline. Study results will produce knowledge that can be used to more efficiently target interventions to FAP patients according to their individual needs and thereby extend evidence-based care to more patients and ultimately reduce overall costs of care.