Mnyambwa NP, et al. – This research inspected the proportion of nontuberculous mycobacteria (NTM) infections among “smear–positive culture–negative” patients diagnosed between January 2013 and June 2016, in Tanzania. It was noted that the isolation of NTM and other bacteria among smear–positive culture–negative samples and the presence of over two third of unconfirmed tuberculosis (TB) cases stressed on the requirement of both advanced differential TB diagnostic techniques and good clinical laboratory practices. This would assist in avoiding unnecessary administration of anti–TB drugs.