The study was commissioned because of the committee's concern about the State's increasing prison population and the inaccuracies in the population forecasts of the California Department of Corrections (CDC). This forecast considered several trends in prison admissions not noted in CDC forecasts. These trends are the high imprisonment rates of blacks and Hispanics compared to whites, the anticipated increase in black and Hispanic male populations aged 15-49 over the next 10 years, and the increase in prison admissions due to more aggressive criminal justice policies. The forecast indicates that by 1995, the male prison population will exceed 100,000 inmates, and 60 percent of these will be black or Hispanic, even though they will represent 30 percent of the State's population. An additional 50,000 prison cells must be constructed by 1995, representing a minimum of 20 new prisons with a capacity of 2,500 beds each. The prison population increase will be principally caused by State legislation adopted during the past 8 years which has lengthened prison terms. Suggestions are offered for improving the CDC's prison population forecasting techniques. 6 charts and 5 tables.