Article InformationThe objective of this study was to estimate HIV infection and associated risk factors among smear positive pulmonary TB patients in Southern Ethiopia. A cross-sectional study design was used to recruit 221 consecutive smear positive pulmonary TB patients visiting three hospitals in Gamo Goffa Zone from March, 2013 to February, 2014. A structured questionnaire was used to collect data on socio demographic, behavioral and economic factors from study units. Chi-square, fisher's exact test and logistic regression were used to assess the association between the above factors and HIV infection among smear positive pulmonary TB. The rate of HIV-TB co-infection among sputum smear-positive pulmonary TB patients in southern Ethiopia was 6.8% with 95% confidence interval of 3.3 to 10.3%. Drinking alcohol was significantly associated with increased risk of HIV infection among smear positive pulmonary TB patients in univariable logistic regression but that association was not maintained after controlling for potential confounding variables. Other factors significantly associated with HIV infection among the study population were previous anti-TB treatment, being resident in urban area and participants who had monthly income of less than or equal to 1000 Ethiopian birr as compared to those who had no regular monthly income. The rate of TB-HIV infection among smear positive pulmonary TB patients in Southern Ethiopia was low. However, the government or other partner organizations should work on decreasing the burden of co-infection through designing strategy on preventing HIV transmission in the urban area; increase the monthly income of citizens while enhancing TB-HIV collaborative activity to prevent reactivation of TB.