Background: During 1998-2007, TB and HIV cases in Bali had shown a significant increase respectively. In general, both of these diseases are chronic diseases that need long term treatment, and together they could worsen the patientsâ€™ condition. To prevent the double burden of those patients, we need to know HIV infection prevalence among TB cases in Bali. Method: One thousands of TB cases diagnosed at TB health services unit (UPK) at primary health centers (puskesmas) and public hospitals in Bali, in September-November 2008, were given information and their blood samples were taken for HIV tests. Samples were chosen proportionally according to the number of TB cases registered in each UPK. Five milliliters of blood sample were taken from each eligible patient by laboratory staff or nurse at the UPK for HIV tests which were conducted at Bali Health Laboratory. HIV test used in this study were the two types of rapid test in accordance with WHO standard. Discussion: Thirty-nine out of 1,000 blood samples were found HIV positive. The highest HIV prevalence among TB cases was in the Buleleng District (11.5%) and followed by Denpasar City (5.1%). This prevalence showed a different figure from the HIV/AIDS cases in VCT clinics registered at Bali Provincial Health Agency, where the highest prevalence found in Denpasar, followed by Buleleng and Badung. If we compare, the difference in figure between Badung and Buleleng, might be due to the difference in routes of HIV transmission. In Buleleng, most of the cases (90%) were sexually transmitted, while in Badung 48% transmission were through injecting drug users. The IDUs seek health services at private health centers and rarely utilize public/government services such as puskesmas and hospitals. Conclusion: The HIV prevalence among TB patients in Bali was 3.9%. The characteristics of the patients showed that they are mostly male, aged between 31-40 years old, have junior high school-university education, divorce or single in marital status, work in private sector, and newly infected extra pulmonary TB/AFB(-) patients. HIV positive cases were not found in all districts, mostly found in Buleleng (11.5%) followed by Denpasar (5.1%), Tabanan (1.8%), Karangasem (1.7%) and Jembrana (1.4%). The proportion of the case detection was high in hospitals, but the spread of the cases at puskesmas was high as well.