Background. Multidrug-resistant tuberculosis (MDR TB) is more difficult to treat and outcomes are worse than for drug-susceptible TB disease. MDR TB cases in Minnesota increased from zero in 2015 to nine in 2016. Case investigations suggested an outbreak. We describe the public health response, challenges of contact investigations (CIs), and ongoing management of contacts. Methods. CDC performed whole-genome sequencing (WGS) to evaluate relatedness of MDR TB isolates. We conducted CIs for infectious cases. We created outbreak specific guidelines for screening and management of contacts, and partnered with various agencies to increase MDR TB awareness. Results. WGS results were consistent with an MDR TB outbreak that included 10 cases (70% pulmonary) as of April 2018. Limited provider awareness about TB contributed to delayed diagnoses. CIs identified 588 contacts; 8.7% (n = 51) of contacts had previously documented positive TB infection test results, and 14% (n = 74) were newly positive for TB infection (median age: 72 years). Eight cases were epidemiologically linked to one Hmong adult day center. Sixty-two contacts started a fluoroquinolone for latent MDR TB infection. Contacts who declined treatment began a 2-year clinical monitoring program. Conclusion. In this outbreak, delayed diagnoses resulted in long infectious periods and hundreds of contacts. WGS results were consistent with recent transmission. We discovered adult day centers are an overlooked congregate setting. CIs were complicated by limited public health funding and high underlying TB infection prevalence in the affected community. Increased community and provider awareness and intensified screening of contacts resulted in additional case finding and prevention interventions.