Statutory reforms of the juvenile justice system came to Canada in 2003 with the enactment of the Youth Criminal Justice Act (YCJA) replacing the Young Offenders Act (YOA) of 1984. The YCJA was a complete overhaul of the juvenile justice system. This article reviews the principal sentencing provisions, as well as the purposes and principles of the new legislation. However, the article begins by describing the context leading to the introduction of the new youth justice statute. It focuses on the likely impact of the YCJA on the use of imprisonment in youth courts and the sentencing principles introduced by the new statute. The statute makes it clear that, although there are important parallels between the purposes and principles, applicable in youth and adult court, there are also significant differences. Rehabilitation assumes a more important role in sentencing youth at the court level and the sentencing purposes that would dispose a court toward the use of incarceration are no longer legitimate considerations in youth court sentencing. The statute prohibits the court from imposing a custodial sentence in many cases in which custody was imposed under the previous legislation, YOA. In addition, the youth court judges have a wide range of sentences at their disposal. Lastly, a court must justify the choice of custody over alternative sentences. The effectiveness of the YCJA in reducing the use of custody depends on the way that criminal justice professionals, especially judges, interpret and implement the statute. Appendix and references