Mycobacterial infection remains as a frequent complication associated to HIV infection. Although the widespread use of HAART has intensely decreased incidence of disseminated Mycobacterium avium (MAC) infection, it does not seem that it has affected tuberculosis occurrence so intensely. In spite of the intense search of new methods of rapid diagnosis, in the clinical practice the diagnosis of the mycobacterial illnesses continues based on culture, although the appearance of new media has allowed to shorten the time of growth. The combination of isoniazid (INH), rifampin (RIF) and pirazinamide (PZ) (with ethambutol [ETB] when primary resistance to INH is higher than 4%), remains as the elective treatment for tuberculosis in HIV infected patients. Due to the interaction between RIF and some antiretovirals drugs, such as proteasa inhibitors, a change in the usual regimens could be necessary. Combinations without RIF or antiretroviral therapy with drugs not interacting with RIF (nucleosides, ritonavir or nevirapin) have been suggested. The emergence of strains of Mycobacterium tuberculosis resistant to the antituberculosis drugs, the lack of adherence to treatment, and the frequency of adverse events hinders even more the control of the tuberculosis and they demand a narrow follow up of these patients. The treatment of the disseminated infection by MAC has improved in the last years with the generalization of the combinations including macrolides as claritromicin or azitromicin with ETB. The doubt persists about what combination is more effective, although like in other opportunists infections associated with a severe immunodeficiency, using antiretrovirals combinations that enhance the immune system could be a fundamental therapeutic approach.