Article 12 of the UN Convention on the Rights of Persons with Disabilities (CRPD) provides that persons with disabilities enjoy legal capacity equal with others and that they be supported to exercise such capacity. This means that they are to make their own decisions in relation to healthcare, accommodation, finance and other personal matters.The imperative to introduce supported decision-making for adults with cognitive disabilities as the default practice has been widely embraced; but the practical way forward for people with profound and severe cognitive disabilities is far from clear. The United Nations Committee on the Rights of Persons with Disabilities interprets the CRPD as prohibiting substituted decision making in all guises and in all cases. The Australian Law Reform Commission and others propose that substituted decision making be retained as “a last resort” and as a protective measure in “hard cases.” But it is important for such representative decision making not to fall back into a paternalistic model. An approach which interprets article 12 in the context of the whole of the CRPD, applying the doctrine of indivisibility of human rights is proposed to enable a human rights-based approach to substituted or representative decision making in cases of severe and profound cognitive disabilities. An interpretation of article 12 through the lens of indivisibility would place the adult with impairment as the subject of rights – especially in upholding economic, social and cultural rights to health, housing, even when a representative may make a decision “as a last resort.”