Decisions about allocation of limited healthcare resources are frequently controversial. These decisions are usually based on careful analysis of medical, scientific and health economic evidence. Yet, decisions are also necessarily based on value judgements. There may be differing views among health professionals about how to allocate resources or how to evaluate existing evidence. In specific cases, professionals may have strong personal views (contrary to professional or societal norms) that treatment should or should not be provided. Could these disagreements rise to the level of a conscientious objection? If so, should conscientious objections to existing allocation decisions be accommodated? In the first part of this paper, I assess whether resource allocation could be a matter of conscience. I analyse conceptual and normative models of conscientious objection and argue that rationing could be a matter for conscience. I distinguish between negative and positive forms: conscientious non-treatment and conscientious treatment. In the second part of the paper, I identify distinctive challenges for conscientious objections to resource allocation. Such objections are almost always inappropriate.