The aim of this study was to determine the nationwide prevalence of smear-positive tuberculosis (TB) in Bangladesh. A multi-stage cluster survey of a random sample of persons aged ≥15 years was included in 40 clusters (20 urban, 20 rural). Two sputum samples were collected from study participants and tested initially by fluorescence microscopy and confirmed by the Ziehl-Neelsen method. The crude and adjusted prevalence rates and 95% confidence intervals (CIs) were calculated using standard methods. A total of 33 new smear-positive TB cases were detected among 52 098 individuals who participated in the study. The average participation rate was over 80%. The overall crude prevalence of new smear-positive TB in persons aged ≥15 years was estimated as 63·3/100 000 (95% CI 43·6-88·9) and the adjusted prevalence was 79·4/100 000 (95% CI 47·1-133·8). TB prevalence was higher in males (n=24) and in rural areas (n=20). The prevalence was highest in the 55-64 years age group (201/100 000) and lowest in 15-24 years age group (43·0/100 000). The prevalence was higher in persons with no education (138·6/100 000, 95% CI 78·4-245·0). The overall prevalence of smear-positive TB was significantly lower than the prevalence estimate of the previous nationwide survey in Bangladesh in 1987-1988 (870/100 000). © 2011 Cambridge University Press.