The present work is the first study on the sequence of whiB7 gene in susceptible, MDR and XDR clinical isolates. No mutation was found in this gene in strains isolated from tuberculosis patients and it was shown that the promoter and structural gene of whiB7 are highly conservative in XDR and MDR isolates. This finding confirmed the need for further studies on designing a proper inhibitor for conservative WhiB7 protein in clinical forms of M tuberculosis.