In Canada the ten provinces and three territories are responsible for their own health laws and services. The 13 mental health acts have core similarities, but there are clinically significant differences. In most Canadian jurisdictions legislation is based on common law; in Quebec, it is based on a civil code. Canadian jurisdictions favour voluntary admission and sometimes make this explicit in their mental health acts. For involuntary admission or compulsory in-patient or community treatment to be valid, three elements must be applied correctly: the process, the criteria and the rights procedures. These are reviewed in this paper.