Background: The assessment of acute stress reactions and psychiatric symptomatology shortly after the occurrence of a traumatic catastrophic event, like an earthquake, is essential for implementing relief activities and for the identification of the long-term aftermath. The aim of our study was to assess the psychological distress and the occurrence of acute stress disorder (ASD) among individuals seeking help at the General Hospital Psychiatric Unit at San Salvatore Hospital following the earthquake at L’Aquila. Factors (sociodemographic, coping strategies, event-related and postevent variables) associated with the acute stress reactions were also assessed. Methods: For the first 4 weeks following the earthquake, 122 help-seekers were assessed with a checklist of traumatic-event-related variables. Measurement instruments included the Stanford Acute Stress Reaction Questionnaire (SASRQ) for the detection of ASD according to DSM-IV criteria, the 12-item General Health Questionnaire (GHQ-12) for assessing psychological distress, and the Brief Cope questionnaire for assessing coping strategies. Results: Despite the high level of psychological distress (GHQ-12 ≥20, cut-off value) found in 65.6% of the subjects, only 6 subjects (4.9%) could be considered affected by ‘full’ ASD, whereas 48 subjects (39.3%) could be considered affected by ‘partial’ ASD, which is defined as showing at least one symptom on each DSM-IV criterion as evidenced by scoring higher than 3 on each SASRQ scale. The strongest predictor of traumatic stress reactions among all the predictor variables included in our study was having been trapped/injured under rubble during the earthquake, and among earthquake stressors (explaining 20% of variance in our model), a weaker predictor was the loss of personal privacy because of home displacement. In our model, more variance (39%) was explained when individual psychopathological variables and coping styles were also included as predictors. Showing coping strategies as exhibiting ‘behavioural disengagement’ or ‘requesting emotional support from others’ were found to increase the likelihood of a positive estimate of being an ‘ASD case’, while the adoption of an ‘acceptance’ coping style seemed to reduce the likelihood of the positive estimate of being an ‘ASD case’. Conclusions: This study underlines the importance of identifying ASD subsyndromal cases and taking appropriate intervention/prevention measures that focus on giving psychological support to individuals trapped/injured under rubble, showing a low acceptance of reality. A relevant underestimated source of distress was the dislocation in large accommodation settings (such as large tent camps) in which individuals lack privacy.