Introduction. According to the Central Institute for Health Informatization of Russia in 2024, 1.3 million people were observed with dependence on alcohol and drugs. Self-questionnaires are used as a tool for assessing the quality of life of patients in a narcological hospital, one of which is EQ5D-3L. The objective of this study was to evaluate the diagnostic performance of the EQ5D-3L Quality of Life Questionnaire for substance abuse patients. Materials and methods. A standardized survey on EQ5D-3L was conducted in the rehabilitation department of the hospital Samara Regional Clinical Narcological Dispensary in March - June 2024. To form indicators, data were grouped by gender, age and type of substance consumed. Results. Of the 121 respondents, 86 were men (71.1%) and 35 were women (28.9%). The average age of men is 39.5 ± 9.4; women - 41.1 ± 9.9. Alcohol users were 74 respondents (52 men, 22 women; 61.2%), mean age 40.8 ± 9.3; drug users - 47 respondents (34 men, 13 women) - 38.8% of the sample, average age: 38.6 ± 9.9. Only 32.2% of respondents rated their condition as "complete health" (population indicator 59.3%; χ 2 = 14.7; p = 0.001). The proportion of people in complete health among alcohol users was 35.1%, among drug users - 27.6%. 13.2% of addiction patients had one component value "2" (population indicator 16.1%; χ 2 = 0.37; p = 0.55). Among drug treatment patients, 40.5% (population 21.9%; χ 2 = 8.4; p = 0.004) had changes in several components. One or more pronounced problem among narcological patients - 14.1% (in a population study - 2.8%; χ 2 = 7.7; p = 0.006). In accordance with the objectives of the study, VAS (EQ-VAS) indicators were also analyzed depending on the gender, age of patients, and type of psychoactive substance. Conclusions. As a result of the study, the EQ5D-3L showed high efficiency. Analysis of the results revealed the group of patients with the lowest quality of life indicators - women who use drugs, with the lowest complete health indicators for the components of the pain/discomfort and anxiety/depression scale.