The present study introduces the Post-Traumatic Embitterment Disorder Self-Rating Scale (PTED Scale), which asks for prolonged and disabling embitterment reactions in the aftermath of negative life events. The PTED Scale was administered to four independent samples of patients and normals. Internal consistency and test-retest reliability were high. Factor analysis indicated a two-factor solution, accounting for 55.25% of the total variance. The PTED Scale discriminated significantly between patients who had been classified according to clinical judgement as suffering from pathological embitterment. Correlations with related instruments demonstrated good convergent validity. Data obtained from a non-clinical sample indicated a prevalence of clinically relevant embitterment in the general population of about 2.5%. The PTED Scale is a reliable and valid measure for embitterment as an emotional reaction to a negative life event. Furthermore, results demonstrate that reactive embitterment in connection to a negative life event is a prevalent phenomenon among clinical and non-clinical populations.