Seniors in a position of vulnerability often give a close family member, usually someone with no experience, a power of attorney to help them manage their affairs. In Québec, powers of attorney are governed by the rules in the Civil Code of Québec dealing with mandates and the administration of the property of others. This research focuses on the decisions rendered by the lower courts in civil cases over a period of 15 years, highlighting the inability of the current legislation to prevent mismanagement by mandataries given power over the property of the elderly. For comparison purposes, the study then examines proposals made in the United States for a legislative framework that will respond more effectively to vulnerable seniors’ need for protection, in the specific areas covered by our research.