The book comprise studies on rifampicin resistance of Mycobacterium tuberculosis in Sri Lanka by sequentially addressing the isolation of Mycobacterium tuberculosis, drug susceptibility testing methods, characterisation of rpoB gene mutations and transmission pattern of rifampicin resistance. Mycobacterium cultures (n=442) were isolated from acid fast bacilli (AFB) positive sputum specimens collected from clinically suspected tuberculosis patients in Sri Lanka. Four hundred and one (401) isolates were identified as belonging to M. tuberculosis complex while the remaining 41 were recognised as belonging to non-tuberculosis mycobacteria group. The prevalence of non-tuberculosis mycobacteria (9.7%) in an acid fast bacilli positive sputum cohort in Sri Lanka indicates the necessity for species identification of Mycobacterium isolates prior to treatment as non-tuberculosis mycobacteria are frequently resistant to conventionally used anti tuberculosis drugs.