Background: Tuberculosis (TB) is a major cause of death in developing countries; it comprisesrnof 25% of avoidable adult deaths. Even though the global burden and incidence rates of TB havernbeen declining since 2004, drug-resistant tuberculosis remains a growing threat to public healthrndespite advances made in treatment and diagnosis over the past decade. Multidrug-resistantrntuberculosis (MDR-TB) which is resistant to at least two drugs of the most powerful first-linerntreatment, rifampicin (RIF) and isoniazid (INH) is one of the challenging problem worldwide.rnEthiopia ranks 15th among 27 high burden MDR-TB countries in the world with an estimatedrn5200 new cases of MDR-TB each year.rnObjective: of the study was to assess the potential determinants of MDR-TB among tuberculosisrnpatients in Addis Ababa.rnMethod: A facility based unmatched case control study design was conducted from December 21,rn2011 to January 30, 2012. Cases were tuberculosis patients with culture-proved mycobacteriumrntuberculosis resistant to at least both to isoniazid (INH) and rifampicin (RIF) and controls werernTuberculosis patients with smear positive mycobacterium tuberculosis who turned negative for thernrecent test after 2nd, 5th or 6th months of treatment course. The case to control ratio was 1 : 2.rnCases were selected from two hospitals which give MDR-TB treatment namely St. Peter andrnDefence Teaching and Referral hospitals. Controls were selected from two hospitals (Federalrnpolice and Defence Teaching and Referral hospitals) and seven health centres. Simple randomrnsampling was used to select patients from the register of each hospital and health centres involved.rnTo identify the determinants a multi variate logistic regression was done.rnResults: A total of 75 cases and 148 controls were interviewed. Among the respondentsrn41(54.7%) of cases and 84(56.8%) of controls were males. The mean (standard deviation) agernamong cases and controls were 30.6(10.4) and 28.6(9.9) respectively. The likelihood of MDR-TBrnwere higher among those who reside out of Addis Ababa ( AOR=18.85 (2.21, 161.10), HIVrninfected (AOR=9.10( 1.48, 54.37) and on previous treatment of TB ( AOR=65.57(14.21, 302.64)rnand proved to be statistically significant.rnConclusion: Previous treatment of TB, HIV infection and residence out of Addis Ababa were thernindependent predictors of MDR-TB and thus needs a better attention of the national TBrnprevention and control activities according to the contextual situations so that to avert the risingrnproblem from the country and furthermore, to keep the health of the community.