BACKGROUND Posttraumatic Diagnostic Scale (PDS) is a self-descriptive measure developed to provide information regarding posttraumatic stress disorder (PTSD) diagnosis and symptom severity. OBJECTIVES THE AIM OF THIS ARTICLE IS TO REPORT ON THE VALIDATION OF THE POLISH VERSION OF PDS AND TO TEST ITS FACTOR STRUCTURE WITH REFERENCE TO TWO MODELS: an original three-factor model (Reexperiencing, Avoidance, and Arousal) and alternative five-factor model (Reexperiencing, Avoidance, Numbing, Dysphoric Arousal, and Anxious Arousal). METHOD THE VALIDATION PROCEDURE INCLUDED THREE STUDIES CONDUCTED ON SAMPLES OF SEPARATE POPULATIONS: university-level students (n=507), individuals who had experienced various traumas (n=320), and treatment-seeking survivors of motor vehicle accidents (MVA) (n=302). Various other measures of trauma-related psychopathology were administered to participants, as well as the PTSD module of the Structured Clinical Interview (SCID) in the case of MVA patients. RESULTS PDS showed high internal consistency and test-retest reliability, good diagnostic agreement with SCID, good sensitivity but relatively low specificity. The satisfactory convergent validity was supported by a large number of significant correlations with other measures of trauma-related psychopathology. Confirmatory factor analysis (CFA) generally confirmed both the three-factor structure and the alternative five-factor structure of the questionnaire. CONCLUSIONS The results show generally good psychometric properties of the Polish version of PDS.