In Canada, persons found NGRI are detained under a Warrant of the Lieutenant-Governor. This provides that such persons be kept in strict custody in the place and in the manner that the court, judge, or magistrate directs until the pleasure of the lieutenant-governor of the Province is known. Review boards have been established under either Federal or provincial legislation to advise lieutenant-governors on the disposition of such persons. The intent of the legislation is to protect society from persons found NGRI until they have recovered from their mental illnesses to the extent they are no longer dangerous. There is little uniformity in the treatment received by persons found NGRI, since whoever heads a treatment unit delivers the treatment he/she has been trained to perform. There are also chronic clinical staffing problems in maximum security hospitals. Further, there are few evaluations and cost-effectiveness studies that have determined whether the existing range of treatment is adequate or effective. Indications are that decisions pertaining to release are conservative and that persons who are not dangerous are maintained in maximum security. Release decisions are largely a function of the nature of the offense while psychiatric assessment data are ignored, suggesting that the length of confinement of persons found NGRI is based to a great extent upon offense severity, which does not distinguish their length of confinement from those found guilty for a similar offense. Also, persons found guilty of a crime but who also manifest mental illness can receive the same treatment administered to those found NGRI. The findings suggest, therefore, that there is little qualitative and quantitative distinction in the handling of those found guilty and those found NGRI in Ontario. Twenty-one references are provided.