The Substance Abuse and Crime Prevention Act (SACPA) represents a major shift in criminal justice policy. Eligible offenders can now be sentenced to drug treatment instead of either supervision without treatment or incarceration. UCLA is conducting an independent evaluation of SACPA that will continue over a 5 1/2 year period ending June 30, 2006. Analysis of data collected during the first year of implementation provides information on the flow of offenders through the SACPA "pipeline" from the initial decision to participate through treatment entry. Also available are characteristics of SACPA clients entering treatment and information on programs treating SACPA clients. Results show that most SACPA-eligible offenders chose to participate in SACPA and that almost two-thirds of those who chose SACPA went on to enter treatment. Also, compared to other treatment clients in California, SACPA treatment clients included fewer women, were older, were more likely to use methamphetamine, and had been using drugs for a longer period of time. Finally, most SACPA clients were referred to outpatient drug-free treatment, regardless of primary drug problem, and very few heroin users in SACPA were referred to methadone. Future reports will cover the possible cost-saving associated with SACPA, outcomes for SACPA clients, and overall lessons learned.