Tuberculosis (TB) is one of the major infectious causes of morbidity and mortality worldwide. TB is difficult to control due to the time taken for the microbiological diagnosis; typically culture on solid media takes 6-8 weeks. There are number of rapid molecular methods that have been developed to diagnose new cases of tuberculosis, detect drug resistance and identify the type of mycobacteria. These assays are based on recognition of mycobacterial DNA sequences and the subsequent amplification of nucleic acid sequences to facilitate detection. This review will describe some of the molecular assays that are in use for TB diagnosis and the considerations in designing and performing such assays. Early diagnosis of tuberculosis is critical for the successful management of patients allowing informed use of chemotherapy ensuring that the right patients are treated with the right antimicrobials.