Objective: To determine the risk factors associated with extensively multidrug-resistant tuberculosis in multidrug-resistant patients in the DIRIS Lima Sur, 2017. Type and design: The type of research was observational and analytical, retrospective case and control. The population consisted of a total of 158 patients who received treatment for MDR-TB between 2016 and 2017. The sample consisted of 24 cases diagnosed with extensively resistant pulmonary tuberculosis (XDR-TB) and 48 controls with MDR-TB. The data collection technique was the survey and the instrument was a questionnaire for both groups (case-controls). Results: 5 internal and external risk factors associated with XDR-TB were identified. Among the internal factors associated at the bivariate level were: drug consumption, having received TB/MDR-TB treatment previously, having received TB/MDR-TB treatment less than one year, having failed to the primary and individualized scheme for TB/MDR-TB (p<0.05); and the multivariate analysis confirmed the influence of the factor "having failed to the primary and individualized scheme for TB/MDR-TB". Among the most associated external factors at the multivariate level were: having relatives who died of XDR/TB-MDR and having neighbors or friends in the neighborhood who died of TB (p<0.05). Conclusion: It was concluded that the factors: "failure to the primary and individualized scheme for TB-MDR-TB"and "having relatives who died of XDR-TB-MDR-TB"are of risk associated with the presence of extensively resistant TB, controlling the effect of risk factors prevents the development of TB.