The projects included pretrial diversion projects, residential alternatives to jail, and alcohol and detoxification programs. Together they constitute California's adult diversion program. The present evaluation was intended to examine the total program rather than individual projects. Projects varied in terms of type of community served and staff characteristics. All were designed to minimize their clients' penetration into the criminal justice system. Client data used in the evaluation were gathered at intake and at 3-month and 6-month followup periods. About three-fifths of the clients in the sample were aged 18 to 30, just under two-thirds were males. Over two-thirds were caucasian, 16 percent were black, and 10 percent were Chicano. Of the 837 clients charged with an offense, 42 percent were charged with petty theft and 21 percent with possession of marihuana. Thus, most of the projects' clients were minor offenders. The case supervision provided by the diversion projects is more intensive than clients would ordinarily receive in traditional programs; this level of supervision prevents the projects from being cost effective since most minor offenders would have received such low cost dispositions as fines and summary probation if tried. Using summary probation as the diversion status and increasing the proportion of cases involving more serious offenses might make diversion more cost effective. The finding that clients made at least three court appearances before being assigned to a diversion project indicates the need for development of a model diversion procedure. In addition, the recordkeeping involved in diversion may have a potentially stigmatizing effect, which diversion is intended to prevent. The Ventura Adult Diversion Project could, however, serve as a model due to its efforts to avoid the establishment and communication of client records. Further descriptions of the projects evaluated and their clients' characteristics are included. Figures, tables, eight references, and appendixes presenting a review of a narcotics addict treatment program, the California Offense Severity Index, a summary table of projects evaluated, and related materials are included. (Author abstract modified)