The article discusses the purposes of mandatory sentencing, reviews the history of mandatory sentencing in the U.S., and identifies its primary statutory forms. Mandatory sentencing laws force jurisdictions to choose between two approaches -- charge-based sentencing and conduct-based sentencing -- for establishing the facts required by mandatory sentence provisions. The author maintains that mandatory sentencing laws are incompatible with the goals of the contemporaneous determinate sentencing movement in that they ignore the total mix of aggravating and mitigating circumstances which should be considered when imposing a sanction. The article explores constitutional issues related to the severity and rigidity of mandatory sentencing provisions and reviews the U.S. Supreme Court decision in Harmelin v. Michigan. Legislatures are urged to reduce the rigidity of sentence enhancement laws and to decrease the severity of most mandatory punishment laws. 327 notes