Despite the educational support role that libraries can play to prisoners in Tanzania as inmates can pursue long distance education and other formal or informal education, no prison in the country has yet to establish a library. This study, therefore, sets out to understand prospects of and challenges to establishing a prison library in Tanzania’s prisons taking two Dar es salaam-based central prisons dubbed X and Y as twin case studies. The study used an explorative qualitative research design to achieve its objectives. Data was collected from purposively and conveniently selected sample of using questionnaires, focus group discussions and in-depth interviews. Of the 300 distributed questionnaires, 222 were returned hence yielding a response rate of 74 percent. There were also three focus group discussion with six prisoners per group and in-depth interviews with the heads of prisons and prison officials overseeing prisoners’ educational programmes. Quantitative data was analysed using SPSS version 20 whereas qualitative data was subjected to content analysis. The study found that prisoners have information needs that are inadequately met. Many of the prisoner respondents (194 (83%, n=194) wanted academic books covering law, health, business to build their knowledge base; 160 (68%) wanted newspapers and magazines; 145 (72%) prisoners wanted religious books; and 99 (43%) prisoners wanted novels and non-fiction books. Many of them (52%, n=142) resorted to borrowing from their fellow prisoners; 69 (25%) were asked friends and relatives to bring needed information on visitation days; 19 (7%) obtained information from prison officials; and a few 41 (15%, n=41) reported not getting any information at all. Under these circumstances, an overwhelming majority of the prisoner respondents (95.5%, n=212) affirmed the need to have a prison library to help them get legal information pertaining to their cases, support their education endeavours via ODL, keep them abreast of the world outside, and for them pass time in their incarceration. Only a handful (4.5%, 10) saw no need to establish a prison library; instead, they called for measures to ease congestion and expediting of trial cases. Challenges facing prison establishment include financial challenges, manpower for the library, facilities and collection development. The study, therefore, recommends for stakeholders’ involvement, government support and financial support for the successful establishment and sustainability of prison libraries. No rehabilitation programme is complete without the library to support information provision and despite their incarceration; prisoners still need information to bridge the gap between them and the outside world. This paper delved into the prospects and challenges of establishing prison libraries in Tanzania. The findings of the study offer insight to the Tanzania Prison Services and societal stakeholders on how the endeavour can be achieved.