Objective: To investigate the impact of childhood trauma on the clinical course of panic disorder and possible contributing factors. Method: Longitudinal data of 539 participants with a current panic disorder were collected from the Netherlands Study of Depression and Anxiety (NESDA). Childhood trauma was assessed with a structured interview and clinical course after 2 years with a DSM-IV-based diagnostic interview and the Life Chart Interview. Results: At baseline, 54.5% reported childhood trauma, but this was not predictive of persistence of panic disorder. Emotional neglect and psychological abuse were associated with higher occurrence of anxiety disorders other than panic disorder (social phobia) and with higher chronicity of general anxiety symptoms (anxiety attacks or episodes and avoidance). Baseline clinical features (duration and severity of anxiety and depressive symptoms) and personality traits (neuroticism and extraversion) accounted for roughly 30–60% of the total effect of childhood trauma on chronicity of anxiety symptoms and on occurrence of other anxiety disorders. Conclusion: After two years, childhood trauma is associated with chronicity of anxiety symptoms and occurrence of social phobia, rather than persistence of panic disorder. These relationships are partially accounted for by duration and severity of anxiety and depressive symptoms, and neuroticism and extraversion.