The aim of this study was to investigate the effect of Type 2 Diabetes Mellitus (T2DM) on sputum negative conversion and treatment of Multi-Drug-Resistant Tuberculosis (MDR-TB). We included a total of 359 MDR-TB patients for comparing the sputum negative conversion rates at 2, 6, and 12 months after initiating treatment and the recovery (treatment success) rates after completion of treatment for patients with T2DM (Group 2DM+) versus those without (Group 2DM-). A total of 20.6% of the patients (74/359) had T2DM; there were no significant differences in the sputum negative conversion rates between Group 2DM+ and Group 2DM- at 2 and 6 months (P>0.05), but the sputum negative conversion rate in Group 2DM+ at 12 months was significantly lower than that in Group 2DM- (P<0.05); the treatment success rates in Group 2DM+ and Group 2DM- were 56.8% and 79.3%, respectively, and the difference was statistically significant (P<0.05). MDR-TB patients with T2DM had a higher recurrent sputum positive rate at the end of the 12-month treatment, and the success rate was relatively low. Therefore, these patients should undergo early screening for MDR-TB and be supervised during the entire treatment course; standardized management and treatment may be able to improve the treatment success rate.