The close connection between tuberculosis and HIV infection was evident since the onset of the epidemic. The spread of HIV has contributed to the increased incidence of tuberculosis world-wide. With the progressively impaired cell-mediated immunity, HIV alters the pathogenesis of tuberculosis and markedly increases the risk of tuberculosis in simultaneously infected subjects. An altered pathogenesis of tuberculosis leads to a more frequent extrapulmonary involvement and atypical radiologic findings. Furthermore, HIV infection is one of the major factors of increased risk of M. tuberculosis multidrug resistance. Even if tuberculosis in HIV-positive patients to some extent can be treated and prevented, it spread in this population is increasing and at present tuberculosis represents the most common opportunistic HIV-related infection several areas world-wide and globally, the first cause of death of HIV-infected patients.