This paper describes the findings of a research project conducted in six adult prisons in New South Wales, Australia that sought to study the information needs and information seeking practices of adult Australian prisoners. Through data gathered from 106 prisoner surveys, the paper identifies the information needs of Australian adult prisoners across six information domains: legal, education, spirituality, health, prison life, and re-integration. For each information domain, participants were asked to identify their preferred source or sources of information from eight possible information sources: prison libraries, tablet devices, staff, family/friends, health services, television/radio, books etc. not from the prison library, or other. The number and nature of unmet information needs are also explored and described. The data gathered enables a study of the different information needs and behaviours of female and male prisoners, and prisoners from across various security levels. The paper finds a significant level of unmet information need in the lives of Australian adult prisoners across all information domains studied. Prisoners are heavily reliant on sources of information that are likely to be non-expert such as custodial staff, other inmates, and family and friends to attempt to meet their information needs about significant critical issues such as their ongoing legal matters and their health. The information needs are similar for female and male prisoners, however their information seeking practices differ, with male prisoners being more likely to have support from family and friends as information sources than female prisoners. Prisoners living in minimum security prisons are least likely to identify a need for spirituality-related information compared with prisoners living in other security classifications and are most likely to seek information regarding their reintegration back into their communities as they plan for their release.