Natural resistance of Mycobacterium tuberculosis to antituberculosis drugs is rare. Drug resistance results primarily from inappropriate treatment. Resistance to antituberculosis drugs, and particularly multidrug resistance (MDR)—defined as resistance to at least isoniazid (INH) and rifampicin (RMP)—prolongs the patient’s infectiousness, thereby increasing the risk of transmission of resistant strains. Resistance to antituberculosis drugs is recognized as a global public health problem. Surveillance of drug resistance is recommended to monitor the effectiveness of tuberculosis control programs. This article presents the results of drug resistance surveillance in Europe in 1999, based on data provided to EuroTB, a surveillance network established in 1996 to improve the contribution of epidemiological surveillance to tuberculosis control in Europe. (R.A.)