The extent of drug resistant tuberculosis (TB) in the capital city of Myanmar, Yangon has not yet been reported. This study aimed to determine the proportion and pattern of drug resistance to first-line anti-TB drugs, among Mycobacterium tuberculosis complex isolates from sputum smear positive TB patients who attended National TB Programme Yangon centres in April-August and October-December 2002. Drug susceptibility was determined by the Mycobacteria Growth Indicator Tube manual system (Becton Dickinson, MD, USA). Of the 567 patients, sputum specimens from 447 (79%) had a positive culture. Of these, 357 isolates (80%) had a susceptibility test result. Isolates from 76 of 259 (29.3%) new patients and from 45 of 98 (45.9%) previously treated patients were resistant to at least 1 of the anti-TB drugs. Resistance to isoniazid (INH) (22.0% vs 40.8%: new vs previously treated patients) and to > or =2 drugs (17.8% vs 29.6%: new vs previously treated patients) was common. Multidrug- resistant TB (MDR-TB) among new and previously treated patients was 4.2% and 18.4%, respectively. INH-resistant (adjusted OR: 2.0, 95% CI 1.1-3.6) and MDR-TB (adjusted OR: 3.4, 95% CI 1.4-8.3) cases were more likely to have taken anti-TB drugs > or =1 month previously. Collectively, prevalence of MDR-TB and TB resistance to > or =2 drugs are not rare in Yangon.