Resistance to anti-tuberculosis (TB) medicines is a major public health threat in most countries of the former Soviet Union. As no representative and quality-assured information on the magnitude of this problem existed in Belarus, a survey was conducted in the capital city of Minsk. Between November 2009 and December 2010, 156 consecutively diagnosed new and 68 previously treated culture-positive TB patients residing in Minsk were enrolled in the survey. Mycobacterium tuberculosis isolates were obtained from each patient and tested for susceptibility to first- and second-line anti-TB drugs. Multidrug-resistant (MDR)-TB was found in 35.3% (95% CI 27.7-42.8) of new patients and 76.5% (95% CI 66.1-86.8) of those previously treated. Overall, nearly one in two patients enrolled had MDR-TB. Extensively drug-resistant TB was reported in 15 of the 107 MDR-TB patients (14.0%, 95% CI 7.3-20.7). Patients <35 yrs of age have shown a two times higher odds ratio of multidrug-resistant TB than those aged >35 yrs. The findings of this survey in Minsk city are alarming and represent the highest proportions of MDR-TB ever recorded in the world. This study greatly contributes to the understanding of the burden of drug-resistant TB in urban areas of Belarus.