Methamphetamine (MA) use is considered as one of the nation's most pressing drug problems. In California, MA use has outstripped all other drugs in epidemiological extent, law enforcement activities, and treatment services demand. An opportunity for further study of MA use and its treatment emerged from a change in offender sentencing options introduced by California's Substance Abuse and Crime Prevention Act of 2000 (SACPA). Results indicate that statewide admissions for MA rose from 8.4% in FY 1992/1993 to 34.6% in FY 2004/2005, a four-fold increase over the 13 years. From the year before SACPA implementation to the year after, the percentage of treatment admissions due to MA use increased from 18.8% to 25.6%, an increase largely due to the fact that SACPA admissions were over 50% MA users. With the exception of alcohol, MA users entering treatment through SACPA had higher completion rates (about one third) from community based treatment than users of other primary drugs. This result held true for demographic and other subgroups of MA users. Multivariate regression results illuminate the relative importance of the variables examined. Implication of the findings for policy, intervention services, and research are discussed.