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BACKGROUND Tuberculosis is one of the commonest opportunistic infections in HIV positive patients. Sputum smear microscopy takes a minimum of 2 days for detection of PTB. In December 2010, the WHO recommended use of CBNAAT in detection of pulmonary TB along with Rifampicin resistance. It takes <2 hours. We wanted to evaluate the CBNAAT positivity in sputum of tuberculosis patients by correlating with sputum smear microscopy and detection of rifampicin resistance. METHODS This is an observational study conducted among 160 patients with age >15 years. All HIV positive patients with sputum positive or sputum negative for PTB were included in the study. All patients with extrapulmonary tuberculosis were excluded from the study. RESULTS Middle aged 26-45 years (68.12%) old individuals are the most commonly affected especially the rural population (84.66%). The population which is more commonly affected is the low education status individuals (primary and high school, 35% and 33.75% respectively); but, among the females, uneducated groups are more commonly affected. Transmission of disease is found to be highest due to sexual contact (73.12%) in which males are more prone (71.55%) and least with I.V. drug abusers (4.38%). By comparing CBNAAT and Sputum AFB positivity, CBNAAT positivity (45%) is found to be more than sputum smear microscopy (15%); it means, CBNAAT positive and sputum AFB negative cases are 31.2%, while CBNAAT negative and sputum AFB positive cases are minimum (1.2%), showing false negativity of sputum smear microscopy and high sensitivity and specificity of CBNAAT. Maximum cases with CD4 count >200, are both CBNAAT and sputum AFB negative and least cases are CBNAAT negative and sputum AFB positive with regard to CD4 count. It is found that 25% were resistant for rifampicin. It helps in screening of MDR patients. CONCLUSIONS CBNAAT helps in the early detection of tuberculosis and it takes less than 2 hours for this. CBNAAT is more sensitive for detection of tuberculosis in HIV positive cases in comparison to sputum smear microscopy. It reduces the false negativity rates. CBNAAT detects drug resistance mainly rifampicin and helps in screening of MDR.