Tuberculosis, inspite of advances in diagnosis and therapeutics still continues to be the leading cause of mortality and morbidity in many developing countries even today. It is one of the major killer infectious disease. In recent years, two important factors which heavily complicate the treatment outcome of tuberculosis patients are MDR-TB and XDR-TB.The mortality in Tuberculosis mainly due to delay in diagnosis. India has the highest TB burden accounting for 1/5 th of Global incidence. The most common form of TB is pulmonary tuberculosis. The sputum microscopy and culture both of them are backbone for the diagnosis of Tuberculosis. The present study aimed to compare and evaluate the of Trisodium Phosphate solution as sputum concentration technique by smear microscopy (Zeihl Neelsen Technique), to compare the smear microscopy. Sputum samples of suspected 150 cases of pulmonary tuberculosis attending Thoracic Medicine and General Medicine OPD at Thanjavur Medical College, (Tamil Nadu) were collected and processed for smear microcopy. Among the 150 sputum samples, AFB positivity in unconcentrated sputum microscopy by Zeihl Neelsen Technique-33(22%),AFB positivity in concentrated sputum microscopy by Zeihl Neelsen Technique-37(25%).The present study confirms that the importance of Trisodium Phosphate solution for sputum concentration technique for the smear microscopy by Zeihl Neelsen Technique.