Background Tuberculosis, mainly in prisoners, is a major public health problem in Ethiopia where there is no medical screening during prison admission. This creates scarcity of TB data in such settings. Objective To determine prevalence and associated factors of TB in prisons in East Gojjam Zone, Northwest Ethiopia. Methods A cross-sectional study was conducted from February to May 2016 among 265 prisoners in three prison sites. Sputum was processed using GeneXpert MTB/RIF. Data were analyzed using SPSS version 20.0. Multivariable logistic regression was used; p values = 0.05 were considered statistically significant. Results Of 265 prisoners, 9 (3.4%) were TB positive (males); 77.8%, 55.6%, and 55.6% of cases were rural dwellers, married, and farmers, respectively. Seven (2.6%) prisoners were HIV positive, and 3 (1.13%) had TB/HIV coinfection. One (0.4%) TB case was rifampicin resistant. Marriage (AOR = 1.5; 95% CI: 1.7, 13.03), HIV (AOR = 0.14; 95% CI: 0.001, 0.17), and sharing of rooms (AOR = 1.62; 95% CI: 2.6, 10.20) were predictors for TB. Conclusion Nine prisoners were TB positive. One case showed rifampicin resistance and three had TB/HIV coinfection. Marriage, HIV, and sharing of rooms were predictors for TB. Prevention/control and monitoring are mandatory in such settings.