This annual Bulletin reports the number of persons in state and federal prisons at yearend. It compares the increase in the prison population during 1994 with that of the previous year and gives the 5- and 10-year growth rates. The Bulletin reports the number of male and female prisoners, the incarceration rates for states, and data on prison capacities and use of local jails because of prison crowding. Data on sentencing and time served describe trends since 1980. Factors underlying the growth of state and federal prison populations are examined.