Background: The Republic of Moldova reports the biggest incidence of tuberculosis (114.3/100.000), the lowest succes treatment rate (52.3%) among European region countries and the biggest default rate among new pulmonary TB cases (10.9%). Material and methods: We studied social, economical,educational, epidemiological and biological features of a total amount of 160 pulmonary tuberculosis new cases, distributed in the study groups, formed of 109 cases, which defaulted the new case antituberculosis treatment and the control group of 51 cured patients under DOTS strategy, having been implemented in the Republic of Moldova since 2001. Statistic evaluation was performed using T Student criteria and Odds Ratio, calculated through the two by two table. Results: According to the predictible value, high risc factors are: solitary matrmonial persons, chronic/abusive alcohol consumption. Low risk factors are: male sex, active smoking, drug injection using,tuberculosis contact, detentional releasing; Neutral value have unempoyement and low educational status. Migration was established as a protective factor. None of medium risk factors was established. Conclusions: Default in the treatment of the patients belonging to economically active and young age groups, socially disadventeged, with harmful habits (alcoholosm, drug injection using, active smoking) and low living conditions. Homeless and detention releasing imperil the continuity of antituberculosis treatment, predisposisng to default the antituberculosis treatment. Social, educational support and withdrawl technics for harmful habits must be implemented to high risk groups for defaulting to minimise the risk of non-adherence.