This report discusses the findings of a nationwide study on the use of private prisons in the United States. The number of these prisons grew enormously between 1987 and 1998, with proponents suggesting that allowing facilities to be operated by the private sector could result in cost reductions of 20%. The study examined the historical factors that gave rise to the higher incarceration rates, fueling the privatization movement, and the role played by the private sector in the prison system. It outlines the arguments, both in support of and opposition to, privatized prisons, reviews current literature on the subject, and examines issues that will have an impact on future privatizations. The report concludes that, rather than the projected 20-percent savings, the average saving from privatization was only about 1 percent, and most of that was achieved through lower labor costs. Nevertheless, there were indications that the mere prospect of privatization had a positive effect on prison administration, making it more responsive to reform.