The shift in 1984 from legislation based in the welfare model tradition of juvenile justice to the modified justice model approach of the new Young Offenders Act has produced dramatic changes in the administration of juvenile justice in Canada. The new legislation strengthened and extended the emphasis on due process and rigorous legal procedure, thereby significantly altering the roles of key players in the juvenile justice system. With the emphasis on the rights of juveniles, due process, and the right to counsel -- including an absolute right to state- funded counsel, independent of parents -- the role of defense counsel has been enhanced in all stages of juvenile justice processing. This has in turn required a strengthening of the role of Crown counsel (prosecutors) to ensure that the procedural safeguards are followed and that the many technical defenses put forward by defense counsel are adequately addressed. The role of youth court judges has been enhanced insofar as they now determine a fixed length of sentence and the level of custody, as well as review their own sentencing decisions. The police role is now more tightly regulated by the parameters of due process. Although probation officers still have a key role in influencing many sentencing decisions, this is secondary to the legal disputations between defense and Crown counsel. An amending bill is before Parliament to lengthen sentences for juvenile murderers and to increase the certainty of transfer to adult court for other serious offenders. 2 notes, 20 references, and appended directory of key juvenile agencies