BackgroundTuberculosis still remains a major public health concern in several provinces of the Democratic Republic of Congo, especially in prison settings. The present study aimed at determining tuberculosis (TB) prevalence and associated risk factors in inmates of the Mbuji-Mayi Central Prison.MethodsThis cross-sectional study was performed over a 6-month period (January to June 2015) in Mbuji-Mayi Central Prison. A total of 733 inmates were screened systematically for TB. The diagnosis was based on clinical examination and bacteriological tests.ResultsTuberculosis was diagnosed in 130 inmates, what amounts to a 17.7 % prevalence (95 % confidence interval [CI] 15.1–20.6 %). The mean age ± SD of infected inmates was 31 ± 9.5 years old, and 94.8 % of them were male. Inmates were detained for a median period of 24 months (range: 3 months to 12 years). A cough lasting more than 2 weeks, body temperature higher than 39 °C, and weight loss were the predominating clinical signs. Factors independently associated with TB infection were overcrowding; highest population attributable fraction ([PAF] 88.2 %; adjusted odds ratio [OR] 9.8 [95 % CI 3.1–31.6]); malnutrition (body mass index of less than 18.5 kg/m2) (PAF 35.6 %; adjusted OR 2.1 [1.3–3.0]); and a detention period equal to or greater than 12 months (PAF 38.7 %; adjusted OR 2.1 [1.4–3.1]).ConclusionsImproving detention and sanitary conditions, as well as providing an adequate and early healthcare, are urgently needed to reduce TB prevalence in the prison environment.