Over the last 10 years, California's institutional population has increased considerably. On June 30, 1989, this population was 82,872, compared with 22,534 on June 30, 1979. Increases in this population are directly due to continuing increases in new admissions to prison and in the number of parole violators returning to prison. Fall 1989 projections indicate that the June 30, 1990, institutional population will reach 94,320 and increase to 135,860 by June 30, 1994 and to 144,820 by June 30, 1995. By June 30, 1990, the number of parolees and outpatients supervised in California is projected to be 61,970, increasing to 96,575 by June 30, 1994 and to 104,260 by June 30, 1995. The total addict institutional population is expected to reach 2,950 by 1995. Factors upon which the projections are based include the male felon admission rate, legislative initiatives, the Inmate Work/Training Incentive Program, California Youth Authority supervision of work furlough and parole cases, work credits for return to custody cases, mean sentences and preconfinement credits, placement need projections, the Substance Abuse Revocation Diversion Program, and parole violators. 19 tables, 5 figures.