Objective：To analyze the drug susceptibility of M.tuberculosis isolates from suspected multidrug-resistant tuberculosis （MDR-TB） patients in Chongqing，so as to provide scientific evidence for MDR-TB discovery and control. Methods：Totally 573 M.tuberculosis isolates from suspected MDR-TB patients were collected from July 2014 to February 2016. Four kinds of first-line anti-TB drugs（INH，RFP，Sm，EMB） and six kinds of second-line drugs（Ofx，Km，Cm，Pto，PAS，Am） were tested for susceptibility by the proportion method. Results：Among the 573 suspected MDR-TB cases，143 cases（25.0%） were identified as MDR-TB，mean－while，55 cases（9.6%） were single drug-resistant tuberculosis（SDR-TB） and 46 cases（8.0%） were poly drug-resistant tuberculosis（PDR-TB）. The proportion of MDR-TB was significantly higher than that of SDR-TB and PDR-TB（P<0.001）. In terms of MDR-TB，the high risk groups had a higher drug resistance rate（26.6%，130/488） than the new patients（15.3%，13/85），P=0.026. Among the high risk groups，the detection rate of MDR-TB was the highest（42.1%，16/38） in the patients who failed in the re-treatment，fol－lowed by those failed in the initial treatment（40.0%，18/45）. Conclusion：The detection rate of MDR-TB is moderately high among the suspected MDR-TB patients in Chongqing. A long way remained to go in controlling MDR-TB. The screening for MDR-TB should target at high risk groups especially the patients failed in the re-treatment and initial treatment.