Background: Hyperglycemia occurs in tuberculosis (TB), but the long-term impact is unknown. We estimated the prevalence of hyperglycemia and compared the TB treatment outcomes and 1-year mortality rate according to the glycemic status noted during TB treatment. Methods: We conducted a retrospective cohort analysis of adult patients who had TB and HIV coinfection and started receiving TB treatment at the Instituto Nacional de Infectologia Evandro Chagas, Brazil, between 2010–2015. Diabetes Mellitus (DM) and hyperglycemia were defined according to the American Diabetes Association. After excluding for known DM at baseline, the proportion of participants who developed new-onset DM after TB treatment was assessed. TB outcome was classified as successful or adverse (i.e., treatment failure, abandonment, and death). Kaplan–Meier survival curves were compared by the log-rank test based on the glycemic status of patients. Multivariate Cox regression models were used to assess the association between hyperglycemia and 1-year mortality. Two-sided p values < 0.05 were considered statistically significant. Results: We identified 414 euglycemic patients (87.5%), 49 hyperglycemic patients (10.3%), and 10 patients with known DM (2.1%). Diabetic patients were older compared to the euglycemic and hyperglycemic patients (47.9 vs. 37 vs. 39.7 years, respectively, p= 0.001). Diabetic patients frequently had cavitation on chest image compared to hyperglycemic and euglycemic patients (50% vs. 23.4% vs. 15.3%, p=0.007, respectively). Hyperglycemic patients had more new-onset DM at follow-up compared to euglycemic (22 vs. 1; p< 0001). Hyperglycemia was associated with adverse outcomes (71.4% vs. 24.6%, p< 0.0001) compared to euglycemia. Crude 1-year mortality was significantly higher in patients with hyperglycemia compared with euglycemia (48.9% vs. 7.9%; unadjusted HR: 5.79 (3.74–8.96)). In the adjusted Cox models, hyperglycemia remained a significant factor for increased 1-year mortality (adjusted HR: 3.72 (2.17–6.38)]. Conclusions: Hyperglycemia frequently occurs in HIV-infected patients who commence TB treatment, and it increases the risks of adverse TB outcomes and 1-year mortality. Glucose testing during TB treatment detects patients at risk of adverse outcomes.