Since the early 1980s, there has been a historically unprecedented increase in the federal prison population. Some of the growth is attributable to changes in federal criminal justice policy during the previous three decades. An issue before Congress is whether policymakers consider the rate of growth in the federal prison population sustainable, and if not, what changes could be made to federal criminal justice policy to reduce the prison population while maintaining public safety. This report explores the issues related to the growing federal prison population. The number of inmates under the Bureau of Prisons' (BOP) jurisdiction has increased from approximately 25,000 in FY1980 to nearly 219,000 in FY2012. Since FY1980, the federal prison population has increased, on average, by approximately 6,100 inmates each year. Data show that a growing proportion of inmates are being incarcerated for immigration- and weapons-related offenses, but the largest portion of newly admitted inmates are being incarcerated for drug offenses. Data also show that approximately 7 in 10 inmates are sentenced for five years or less. Changes in federal sentencing and correctional policy since the early 1980s have contributed to the rapid growth in the federal prison population. These changes include increasing the number of federal offenses subject to mandatory minimum sentences; changes to the federal criminal code that have made more crimes federal offenses; and eliminating parole. There are several issues related to the growing federal prison population that might be of interest to policymakers: The increasing number of federal inmates, combined with the rising per capita cost of incarceration, has made it increasingly more expensive to operate and maintain the federal prison system. The per capita cost of incarceration for all inmates increased from $19,571 in FY2000 to $26,094 in FY2011. During this same period of time, appropriations for the BOP increased from $3.668 billion to $6.381 billion; The federal prison system is increasingly overcrowded. Overall, the federal prison system was 39% over its rated capacity in FY2011, but high- and medium-security male facilities were operating at 51% and 55%, respectively, over rated capacity. At issue is whether overcrowding might lead to more inmate misconduct. The results of research on this topic have been mixed; The inmate-to-staff ratio has increased from 4.1 inmates per staff member in FY2000 to 4.9 inmates per staff member in FY2011. Likewise, the inmate to correctional officer ratio increased from 9.8 inmates per correctional officer in FY2000 to 10.2 inmates per correctional officer in FY2011, but this is down from a high of 10.9 inmates per correctional officer in FY2005; The growing prison population is taking a toll on the infrastructure of the federal prison system. The BOP reports that it has a backlog of 154 modernization and repair projects with an approximate cost of $349 million for FY2012. Past appropriations left the BOP in a position where it could expand bedspace to manage overcrowding but not reduce it. However, reductions in funding since FY2010 mean that the BOP will lack the funding to begin new prison construction in the near future. At the same time, it has become more expensive to expand the BOP's capacity. Should Congress choose to consider policy options to address the issues resulting from the growth in the federal prison population, policymakers could choose options such as increasing the capacity of the federal prison system by building more prisons, investing in rehabilitative programming, or placing more inmates in private prisons. Policymakers might also consider whether they want to revise some of the policy changes that have been made over the past three decades that have contributed to the steadily increasing number of offenders being incarcerated.