Decision-making in the context of dementia can pose an interesting challenge to the health care professional. Persons with mild-to-moderate dementia can have the capacity to make some, but not all, decisions. They may be able to participate in decision making but impaired memory recall might preclude their ability to demonstrate that they understand the treatment options. This short article discusses the key legal and ethical considerations involved in the decision-making process, emphasizing that whether or not an individual has the capacity to understand, make a decision and take responsibility for the consequences of the decision is a clinical determination and not a question of legal competence.