In this article, we present MARC, a model for assessing – and improving – the health of organisationsfrom a humanistic point of view. It is a part of the quest for sustainability, currently a main theme inorganisations. The components of MARC: Meaning, Authority, Rationality, and Care, are four aspectsthat are all needed, and need to be in balance in an organisation, to provide a work situation wherepeople can sustainably thrive rather than be damaged and consumed for the sake of the organisation.Implications of the model are discussed. A conclusion is that trust is central to this healthy balance.This presents a real challenge for sustainability, as trust takes time to build – but can quickly beerased.