Background: In developing countries, quality of prison life remains a challenge in public health. The present study aimed at determining the quality of life as perceived by inmates during their imprisonment at the Central Prison of Mbuji-Mayi, Democratic Republic of Congo. Methods: This cross-sectional study was carried out over a 3-month period (between December 2015 and February 2016) at the Central Prison of Mbuji-Mayi. Three hundred inmates participated to the survey. The World Health Organization Quality of Life Scale (WHOQOL-BREF) was used to estimate health and problems affecting inmates’ everyday life. Results: Mean age of inmates was 33 ± 10 years (range: 18-70 years) and most of them were male (88.7%). The quality of life score estimated was below 50, on the WHOQOL-BREF scale weighted over 100 points (average overall score: 26 ± 7). When considering each WHOQOLBREF domain, the lowest scores (0-100 normalized scale) were registered for: perception of physical health (24 ± 11), psychological health (18 ± 8), social relationship (39 ± 15) and environmental relationships (24 ± 8). Overall, inmates aged over 30 years old presented an average score slightly lower than younger inmates (25 ± 6 vs. 27 ± 7; p=0.005). Depending on the length of incarceration, the average score was lower for inmates imprisoned for more than 6 months compared to others (26 ± 6 vs. 28 ± 8; p=0.015). Correlations between domain scores were low but statistically significant; no correlation was highlighted between environment and mental health domains. Conclusion: Most inmates considered their quality of life as negative, regardless of the WHOQOL-BREF domain. Efforts to improve quality of life should remain a priority for political authorities.