SETTING: Pakistan ranks fourth among the countries with a high burden of multidrug-resistant tuberculosis (MDR-TB), with only 19.2% of the 15 000 estimated incident cases being notified. Increasing treatment coverage for MDR-TB is a key priority for Pakistan's National Tuberculosis Programme. The World Health Organization recommends the use of the Xpert® MTB/RIF assay as the first-line diagnostic test for individuals with presumed TB. OBJECTIVE: To describe a multifaceted case-finding intervention targeting public and private sector health care facilities that used the Xpert assay as a frontline diagnostic test for individuals with presumptive TB, in Karachi, Pakistan, and its impact on case notifications of MDR-TB. DESIGN: Cross-sectional study. RESULTS: A total of 51 168 individuals were tested using Xpert, of whom respectively 7581 and 1534 people were diagnosed with TB in the public sector (reverse public-private mix) and private sector (social business model) arms; 574 (6.3% of all TB cases) were identified as having rifampicin (RMP) resistance. A total of 517 (90.1%) people with RMP-resistant TB (RR-TB) identified through the project were initiated on second-line treatment. The intervention resulted in 194 additional cases of RR-TB, an increase of 43% over the baseline. CONCLUSION: This project, one of the largest Xpert testing programmes conducted at city level, resulted in significantly increased detection and treatment of MDR-TB.