This study was conducted at the New Delhi Tuberculosis Center, Delhi, India, from 1 January 2006 to 31 December 2007 to assess the feasibility of implementing random blinded rechecking (RBRC), a quality assurance strategy, and its impact on the performance of tuberculosis smear microscopy in Delhi, RBRC activities are carried out monthly at District Tuberculosis Centers (DTCs). Forty thousand five hundred and six slides were rechecked during the study period. RBRC, as a method of quality assurance was found to be feasible for a large application. The quality of sputum microscopy improved, with a significant reduction in the number of false positive and false negative errors in 2007 compared to 2006. The number of microscopy centers reporting high false errors decreased significantly in 2007.