Epidemiological indices of tuberculosis (TB) rest very high in Republic of Moldova (RM). According to the World Health Organization (WHO), our country ranks in the list of 30 high multidrug-resistant tuberculosis (MDR-TB) burden countries (25% of new cases and 61% of retreated cases are MDR-TB) showing the lowest treatment results: 2010 – 58,7%, 2011 – 63,7%, 2012 – 62,6%, 2013 – 76,6%, 2014 – 75,8%, comparing with WHO recommended target of 85%. One of the most important index, contributing to low values of treatment success is the outcome of treatment failure, that was the highest among European region countries: 2010–19,6%, 2011–17%, 2012 – 16,4%, 2013 – 3,8%, 2014 – 3,2%. According to the national policy the management of TB patients and case-finding is mostly performed by passive way through microbiological investigation of the symptomatic case. Usually passive detection contributes to the delayed diagnosis, in consequence one third of patients being infectious (microscopic positive for acid-fast-bacilli), and identified with severe and extensive infiltrates complicated with lung destructions. Associated biological risk factors (male gender, age group) and social conditions (economic vulnerability, migration, homelessness, history of incarceration, alcoholism, HIV infection, and intravenous drug use) contributes to failure of treatment outcome and acquiring of drug-resistance. MDR-TB is a form of infection, caused by Mycobacterium tuberculosis resistant to at least two most powerful first line anti-TB drugs: isoniazid and rifampicine. Treatment of MDR-TB is based on the directly observed therapy, as a part of DOTS Plus Strategy: daily administration of second-line TB drugs during 18–24 months, government commitment to TB control, case detection through microbiological methods, free therapy administrated under direct observation and monitoring of treatment outcomes. The current study aims to assess biological, social, epidemiological, clinical and radiological risk factors predisposing MDR-TB treatment failure. Treatment outcome defined as MDR-TB treatment failure is the patient which is positive at two or more of five cultures recorded at the end of 12 months of therapy. Outcome was defined as successful by including cured patients and patients who completed treatment according to the national protocol. A selective, retrospective research included a study group (SG) composed from 24 cases with MDR-TB treatment failed patients and control group (CG) which included 105 successfully ended the treatment. Were assessed target indices: biological factors, social conditions, epidemiological factors, clinical, radiological and therapy factors. Univariate analysis on the relationship between treatment failure and biological and social risk factors showed an association between: male sex comparing with female 79% in SG vs. 62% from CG (p<0,05), age more than 45 years old 75% of SG vs. 42% of CG (p<0,001), TB contact 42% of SG vs. 39% of the CG, affiliation to an MDR-TB cluster 23% vs. 42% (p<0,01), living under the poverty limit 67% of SG vs. 62% of CG, active smoking 88% of SG vs. 82% of CG, chronic alcohol consumption 65% of SG vs. 48% (p<0,01). Clinical and radiological predisposing conditions were: late detection (more than 3 months from the clinical onset) 92% vs. 58%, extensive radiological forms 100% vs. 45%, previous TB treatment 0% vs.45%, TB-HIV co-infected 0% vs. 8%. It can be concluded that the hierarchy of risk factors for MDR-TB treatment failure consists in radiological extensiveness, late detection, previous treatment, male sex and old age. Assessment of the predisposing conditions for treatment failure permits implementing risk reduction measures for enhancing treatment outcome.