The present study investigated the extent of dysfunctional appraisal as measured with the Posttraumatic Cognitions Inventory (PTCI) and physiological responses to trauma-related material in patients with acute stress disorder (ASD; N=44) in comparison to participants without trauma exposure (N=27). Heart-rate (HR), skin conductance responses (SCR), and viewing time were recorded in response to - for trauma victims - idiosyncratically trauma-relevant and control pictures. ASD patients evidenced greater dysfunctional appraisal than control participants with regard to the PTCI scales Self and World and also an accelerative HR reaction and greater SCRs to trauma-relevant pictures. Among patients, PTCI was highly correlated with ASD severity while PTCI World was positively correlated with resting HR and depression. Amplitude of the HR reaction to trauma-related pictures was negatively correlated with viewing time. Results suggest that dysfunctional appraisal and autonomic reactivity are only loosely related in ASD.