BackgroundDrug-resistant tuberculosis continues to be a public health threat around the globe especially in developing countries. In 2018, the number of new cases of rifampicin-resistant tuberculosis was half a million and about 78% of them had multi-drug resistant tuberculosis. In Ethiopia, the overall proportion of multi-drug resistant tuberculosis was 11.6%. The latest treatment outcome data for people with multi-drug resistant tuberculosis show a global treatment success rate of 56%. Therefore, this study was aimed at assessing multi-drug resistant tuberculosis treatment outcomes and associated factors at St. Peter Specialized Hospital, Ethiopia, 2019. MethodsA retrospective cross-sectional study was done. A total of 384 patient medical charts selected by simple random sampling method were reviewed. The data was collected using a checklist from the patients’ medical charts. The collected data were analyzed with SPSS version 23 computer software package. Summary statistics of a given data for each variable were calculated. A logistic regression model was used to measure the association between the outcome and the predictor variable. Statistical significance was declared at p-value<0.05. Direction and strength of association were expressed using OR and 95% CI. ResultFrom a total of 384 patients, the majority of 245(63.8%) of the study subjects were females. The rate of poor treatment outcome was 173(45.1%). Male patients and patients in the age category of 39-60 years were less likely to have poor treatment outcome compared to female patients and patients in the age category of 18-38 years (AOR = 0.43, 95%CI (0.19, 0.10) and (AOR = 0.28, 95%CI (0.15, 0.52) respectively. Patients with a history of second-line TB drug resistance are more likely to have poor treatment outcomes (AOR = 3.81, 95%CI (1.84, 7.91). Poor treatment outcome was higher among patients with longer treatment duration (AOR = 3.23, 95%CI (1.82, 5.74) compared to patients with short treatment duration. ConclusionThe proportion of poor treatment outcome in patients with multi-drug resistant tuberculosis was high. Therefore, a concerted effort should be done at all levels to improve the treatment outcome of the MDR-TB.