Nineteen children born to patients with panic disorder and a comparison group of 16 children born to unaffected, non-psychiatric patient subjects exposed to novel and mildly stressful situations (visiting an unfamiliar place and watching a movie containing anxiogenic scenes) were assessed for their behaviors, heart rate, respiratory rate and salivary cortisol secretion. At arrival children born to patients with panic disorder had significantly longer latency of first spontaneous verbal comment, fewer prosocial behavior, and increased distress and attachment behavior. During the projection of the movie, children of the two groups differed for attachment, distress, and exploration behaviors. During the anxiogenic scenes children born to patients with panic disorder showed increased behavioral inhibition and higher heart rate. Autonomic modulation, respiratory rates and cortisol secretion were similar in the two groups. Some distinct psychophysiological patterns may constitute early manifestations of the transmitted liability to panic disorder.