The magnitude of anti-tuberculosis drug resistance in Bangladesh is not precisely known. We studied the drug resistance patterns of Mycobacterium tuberculosis in an urban and a rural area of Bangladesh. A tuberculosis (TB) surveillance system has been set up in a population of 106,000 in rural Matlab and in a TB clinic in urban Dhaka. Trained field workers interviewed all persons > or =15 y at Matlab to detect suspected cases of tuberculosis (cough >21 d) and sputum samples were examined for acid-fast bacilli (AFB). The first 3 AFB positive patients daily from the urban clinic were included. AFB positive cases diagnosed between June 2001 and June 2003 from both settings were cultured and drug susceptibility tests were performed. Of 657 isolates, resistance to 1 or more drugs was observed in 48.4% of isolates. Resistance to streptomycin, isoniazid, ethambutol and rifampicin was observed in 45.2%, 14.2%, 7.9% and 6.4% of isolates, respectively. Multidrug resistance was observed in 5.5% of isolates. It was significantly higher among persons who previously had received tuberculosis treatment of > or =1 month (15.4% vs 3.0%, adjusted OR: 6.12, 95% CI: 3.03-12.34). The magnitude of anti-tuberculosis drug resistance in Bangladesh is high. Further evaluation is needed to explain the high proportion of streptomycin resistant M. tuberculosis. Appropriate measures to control and prevent drug resistant tuberculosis in Bangladesh to reduce mortality and transmission are warranted.