A substitute decision-maker is a person who is chosen to make health care decisions for you should a severe illness or injury prevent you from making these decisions for yourself. The document that grants this decision-making power to the person selected is called a personal directive, representation agreement, or another name depending on the province or territory.

A substitute decision-maker may also be called a health care agent, representative, or proxy.

Although laws vary by province or territory, a decision-maker can usually make treatment decisions (if health professionals agree with these decisions) at the end of life or anytime a person is not able to communicate. As soon as you select a decision-maker, it is important to thoroughly discuss and document health care preferences, such as when to continue or abandon life-support measures.