Describes a research project carried out at the Department of Information and Library Studies, University of Wales, Aberystwyth, to develop a series of performance indicators for use in evaluating prison libraries so as to improve the effectiveness and efficiency of such services. Research completed to date involves a litera ture survey and a pilot study. The purpose of the pilot study was to assess current practice in prison libraries, and involved opinion leader interviews, selection of test sites, structured interviews with prison staff and inmates, observation and monitoring. Having assessed perfor mance indicators, care was taken to allow for the problems arising from the prison regime. Six test sites were involved in the inmate interviewing programme and the aim was to talk to a minimum of 10 per cent of the pop ulation at each test site. Sites included two women's prisons (one open and one closed), and four men's prisons (one dispersal, one category B local, one category C and one Young Offender Institute).