Psychometric properties of "The Level of Relatives' Emotional Burnout" measure (LREB) based on a sample of 297 chemically addicted patients' relatives are presented. The assessment tool was developed with regard to the field of application - the interaction of family members. Along with the classical burnout symptoms (exhaustion, depersonalization, and personal achievements reduction), LREB makes it possible to evaluate aspects of the informal caregivers' personal activity (in particular, dedication, self-efficacy in the treatment of the ill relative), which potentially protect from burnout as a result of taking care for the chronically ill relative. The analysis revealed good psychometric characteristics of the LREB in terms of reliability, internal structural, convergent and divergent validity.