Time-series data for the 1985-95 period were obtained from the California Department of Justice, Uniform Crime Reporting Program. The three-strikes law had little observable influence on either the California Crime Index rate or the petty theft rate. The article discusses several possible explanations for the law's negligible effect on serious crime: (1) current sentencing practices already confine a substantial proportion of high-risk offenders behind bars; (2) the effectiveness of three-strikes legislation as a crime control strategy depends on the duration of criminal careers (by the time offenders are confined for their third strike, their criminal careers usually are on the decline, if not concluded); and (3) juvenile offenders in California are not affected by the three-strikes law, so it seems unlikely that juvenile crime was affected in any substantial way by the three-strikes law. Figures, table, notes, references