The morbidity of primary and secondary drug resistance (DR) of Mycobacterium tuberculosis (MBT) was studied in the North-West of Russia during 1991-2001. The frequency rate and structure of, mainly, secondary DR MBT was investigated in tuberculosis of different localizations on the basis of data provided by clinics of Saint-Petersburg Research Institute for Phthisiopulmonology (PRIP) during 1990-2000. A sharp increase of primary DR MBT (in the North-West of Russia) up to 35-45.5% was detected in the Murmansk, Arkhangelsk and Saint-Petersburg Regions as well as in the Republic of Karelia, an increase of up to 61% was registered in the Kaliningrad Region. The frequency rate of secondary DR MBT went up by 1.5-2 times reaching 80-86% in the Murmansk, Arkhangelsk and Kaliningrad Regions. According to the PRIP clinics, there is also an essential growth of DR MBT in all tuberculosis localizations with a trend of the stability structure shifting towards poly-resistance, which accounts for 65.2% in pulmonary tuberculosis and for 33.6% in extra-pulmonary tuberculosis.