The study investigated correlates of functional disability in 94 patients (89.4% women, 10.6% men; mean age=34.2 years) with postural tachycardia syndrome (POTS), a clinical syndrome of orthostatic intolerance characterized by significant functional limitations. Path analysis supported a model in which, controlling for demographic and disease variables, catastrophic cognitions were directly related to the latent variable functional disability, whereas somatic vigilance, anxiety sensitivity, and neuroticism were indirectly associated with functional disability through their relationship with catastrophic cognitions. Results suggest that modifiable psychological factors play a role in the functional limitations experienced by patients with POTS. Longitudinal research is necessary to confirm these relationships.