Introduction: Lima and Callao are high risk areas for tuberculosis active transmission in Peru. Multidrug-resistant tuberculosis represents 5.54% of the new cases of pulmonary tuberculosis (primary MDR-TB) in Lima and Callao. Involved risk factors have not been studied in patients from Callao. Objectives: To determine risk factors for primary MDR-TB in patients attending health care facilities in Callao during 2009-2010. Design: Case-control study. Setting: Health care facilities from Callao. Participants: Twenty nine primary MDR-TB patients and 37 drug-sensitive TB patients were studied through assessment of the Tuberculosis Control Program Registries and healthcare facilities’ clinical records. Interventions: Information was obtained from secondary sources. Odds-ratios were calculated by bivariate analysis. Logistic regression models were used to calculate multivariate odd-ratios. Ma...