These new guidelines give important proposals for the treatment of multidrug-resistant tuberculosis (MDR-TB). However, most of them are based on expert opinion, without good evidence. The new guidelines are the following: I. Rapid sensitivity testing of isoniazid and rifampicin or of rifampicin alone is recommended over conventional testing or no testing at the time of diagnosis of tuberculosis, subject to available resources. II. The use of sputum smear microscopy and culture rather than sputum smear microscopy alone is recommended for the monitoring of patients with MDR-TB during treatment. III. In the treatment of patients with MDR-TB the following rules are given: 1) a fluoroquinolone should be used; 2) a later-generation fluoroquinolone rather than an earlier-generation fluoroquinolone should be used; 3) ethionamide (or prothionamide) should be used; 4) four second-line anti-TB drugs likely to be effective (including a parenteral agent from among the second-line injectables kanamycin, amika-cin or capreomycin), as well as pyrazinamide, should be included in the intensive phase of treatment; 5) regimens should include at least pyrazinamide, a fluoroquinolone, a parenteral agent (kanamycin, amikacin or capreomycin), ethionamide (or prothionamide), and either cycloserine or p-aminosalicylic acid (PAS) if cycloserine cannot be used; 6) an intensive phase of 8 months' duration is recommended. 7) a total treatment duration of 20 months is recommended in patients without any previous MDR-TB treatment. IV.- Anti-retroviral treatment is recommended for all patients with HIV and drug-resistant TB requiring second-line anti-TB drugs, irrespective of CD4 cell count, as early as possible (within the first 8 weeks) following initiation of anti-TB treatment. V.-Patients with MDR-TB should be treated using mainly ambulatory care rather than models of care based principally on hospitalization.