Recently, major advances have been accomplished in the diagnosis of active tuberculosis. A comprehensive diagnostic approach for a patient with possible tuberculosis includes a detailed medical history and clinical examination as well as the results of radiological, microbiological, immunological, molecular-biological and histological methods. In concert, these results enable the clinician to rapidly develop a decision with a high probability for the diagnosis or exclusion of active tuberculosis. Therapeutic intervention can thus be made early, even though corrections in these decisions need to be considered depending on the results of Mycobacterium tuberculosis culture and sensitivity testing.