The quality of life of the general population in Nigeria remains poor due to the high level of poverty and poor conditions of social services including health care. Prison inmates suffer the most because successive governments neglect the prisons. The situation has challenged the prison's rehabilitation programs. This study investigated how inmates of the Ilesa Prison in the Osun State of Nigeria perceived their quality of life. The study employed a descriptive research design and was carried out at the Ilesa Prison in Osun State, Nigeria; 140 inmates participated in the study. The World Health Organization Quality of Life Scale (WHOQOL-BREF) was adapted and used to determine the inmates' perception of their general quality of life during confinement. The data collected were analyzed with descriptive and inferential statistics. The findings showed that the calculated F-ratio of 19.345 for inmates' perception of poor general quality of life was significant at p = 0.100 when tested at a 0.05 level of significance. It was further revealed that the calculated F-ratio of 27.527 for inmates' perception of their physical health was significant at p = 0.100 when tested at a 0.05 level of significance. While considering the inmates' psychological wellbeing perception, the calculated F-ratio of 25.243 was significant at p = 0.110 when tested at a 0.05 level of significance. Also, the calculated F-ratio of 10.197 for inmates' perception of their social well-being was significant at p = 0.100 when tested at a 0.05 level of significance. The Ilesa Prison inmates have poor perceptions of their physical health and their social and psychological well-being. It was concluded that inmates' general quality of life was poor during imprisonment. Authorities of the Nigerian Prison Service (NPS) should put necessary programs in place to improve inmates' quality of life to achieve the rehabilitation objectives of imprisonment.