Background Information: Studies of Antiretroviral Therapy program in Africa have shownrnhigh incidence rate of tuberculosis in both Antiretroviral Therapy receiving and AntiretroviralrnTherapy naÃ¯ve Human Immunodeficiency Virus infected patients. Tuberculosis incidence andrnfactors that contribute for development of tuberculosis in era of Antiretroviral Therapy werernpoorly described in Ethiopia.rnObjective: To examine the effect of HAART on incidence rate of tuberculosis and tuberculosisrnfree survival among HIV-positive adults in HAART receiving and HAART naÃ¯ve groupsrnenrolled to ART clinic in Hawassa University Referral Hospital.rnMethod: A retrospective cohort study design was used on 632 HIV-positive adults with age 15rnyears old and above enrolled to ART clinic in Hawassa University Referral Hospital over arnthree-year period. Incidence rate of tuberculosis and TB free survival was calculated andrncompared for Pre-HAART and HAART follow up HIV/AIDS patients. In this study, patientsrnwho followed on Pre-HAART are considered as unexposed and patients who receiving HAARTrnconsidered as exposed, and was followed for three years from July 2006 to January 2011.rnResult: A total of 632 patients (316 in ART and 316 in ART cohort) followed for a median ofrn32.9(IQR=17.6-36.5) months in Pre-HAART and 35.4 (IQR=23.6-36.5) months in HAARTrncohort. TB incidence rate was 3.5 and 7.2 per 100 PYO in HAART and Pre-HAART cohortrnrespectively. Over all chance of not developing TB was high in HAART cohort (Log rank=8.24,rndf=1, P=0.004). Being on HAART (AHR=0.182, 95%CI=0.078-0.424, P