In 1982, the Illinois Legislature enacted a statute that based most transfers from juvenile to adult courts on the charged offense. Prior to this legislation, the juvenile court judiciary was mandated to determine which were the most appropriate transfers. This study examined data on juvenile cases transferred from Illinois juvenile court to criminal courts for 1974-82. The final sample of cases consisted of 346 youth transferred. Data were collected on who has been transferred and what happened to them during the pretrial period and in the disposition. The experience in New York State under a similar law was also examined. There is ample evidence, even with no access to the earlier offense histories of the youth, that the juveniles transferred to criminal court under the old law were serious offenders. Detention time for youth transferred has been extremely long compared with the time normally spent in detention under the juvenile court's jurisdiction. The differences between original charges and sentenced charges indicate the routine use of charge reduction; this practice will have a profound impact on cases under the new law. While about 85 percent of the youth in the sample would be removed to criminal court under the new law, only 48.3 percent of the total would be retained for trial or sentencing, because charges would have been reduced. There is some evidence that expected sentences could be substantially greater for youth convicted of murder as well as for youth convicted of rape and armed robbery. When the limited data about sentence is added to the information that (1) there is no sentence in a substantial number of transferred cases and (2) under the proposed law an additional number of youth would be held at the juvenile court for trial or sentenced in criminal court under the juvenile code, then the ability of the new law to ensure more certain and severe sentences is called into question. Data from similar New York legislation indicates that the vast majority of those cases in which an arrest is made for a mandatory transfer crime will be filtered out of the criminal court. Further, for the youth retained at criminal court, the costs can be loss of the services and treatment provided by the juvenile system but lacking in the adult system. The greater procedural protections in adult courts may increase the chance of receiving no sentence. Tabular and graphic data are provided.