Background:In the developing countries, Tuberculosis is one of leading causes of morbidity and mortality. The detection and identification of Mycobacterium tuberculosis is considered a great challenge for clinical microbiologists. Albeit Ziehl-Neelsen (ZN) smear is being a rapid diagnostic tool for TB, the culture on Lowenstein Jensen (LJ) medium is considered the golden diagnostic tool for TB in the developing countries.Objectives: To evaluate the validity and reliability of ZN smear of acid-fast bacilli compared to the culture on LJ medium. Patients and methods:The retrospective analytic comparative cross-sectional study included patients visiting TB OPD clinic at NCDC, including transferred patients from other healthcare facilities and hospitals. A total of 2783 specimen of suspected pulmonary TB cases were processed for both direct smear and culture. The direct smears were stained with ZN method (1% Carbolfuchsin, 3% Hydrochloric acid Ethanol and 0.1% methylene blue). Specimens were observed under 100-x oil immersion lens, whilst cultures were inoculated on LJ medium after digestion and decontamination of the clinical specimens.Results: Of total 2783 study subjects, 203 (7.29%) were smear positive while 327 (11.74%) were culture positive. Out of 203 smear positive pulmonary cases, 154 (47.094%) were found to be positive on LJ culture. A total of 2407 pulmonary cases were negative on the smear and LJ culture for Mycobacterium tuberculosis.Conclusion: This preliminary study indicated the low sensitivity of sputum smear direct microscopy for early diagnosis of TB, while culture on LJ remains the golden standard modality.