Tuberculosis caused by Mycobacterium tuberculosis is rampant in human and animals; it has been classified as reemerging disease as it is being reported with increasing frequency in human particularly from developing countries. Early diagnosis of the disease by using sensitive, specific, rapid & cost effective diagnostic procedure is of utmost importance for effective control. Although several modern methods like BACTEC, ATP Bioluminescent, Biological Oxygen uptake assay, MGIT, r-RNA viability etc. are available for clinical use. These techniques are rapid, radioactive (BACTEC), sensitive, specified but require heavy financial commitment and their high cost limit practical applicability. The present study was undertaken to evaluate the Alamar Blue assay which is a simple & less costly technique as a diagnostic tool for tuberculosis. Increasing reports of tuberculosis in man and animals suggest development of multi-drug resistance in M. tuberculosis. Therefore, use of antibiotics on the basis of in-vitro drug sensitivity testing seems rational and justified.