This article explores the regulation of people with mental illness who are accused of committing minor crimes (e.g. mischief, minor theft, assault, uttering threats, etc.) and viewed as disturbing the public order. The results are drawn from a study of a Mental Health Court (MHC) in Montréal (Canada), illuminating the perceptions and experiences of MHC actors who are involved in its operation. Deploying a multi-method design inspired by institutional ethnographic methods, this study sought to explore the inherent tensions in regulatory penal practices that oscillate at varying degrees between prevention, punishment and therapeutic intentions. It is argued that MHCs symbolize a new form of governmentality, in an eff ort to create disciplined subjects by reigning in madness and controlling marginality.