TB/HIV co-infection is associated with poorer treatment outcomes compared to TB alone. This study assessed the TB treatment success rate and its predictors among TB/HIV co-infected patients in East and North Eastern Uganda. A retrospective cohort design was used, involving 324 patients treated between July 2019 and July 2021 at three regional referral hospitals. Treatment success, defined as completing therapy with or without bacteriologic confirmation, was achieved by 71.9% of patients (95% CI 67-77%). Loss to follow-up was 12%, mortality 9.9%, treatment failure 0.3%, and 5.2% were not evaluated. Patients lacking sputum monitoring at five months were significantly less likely to achieve treatment success (aRR 0.48, 95% CI 0.34-0.66). These findings underscore the importance of effective follow-up to improve outcomes for TB/HIV co-infected patients.