This article is about the justifiability of accepting worse cost effectiveness for orphan drugs, that is, treatments for rare diseases, in a publicly financed health care system. Recently, three arguments have been presented that may be used in favour of exceptionally advantageous economic terms for orphan drugs. These arguments share the common feature of all referring to considerations of justice or fairness: the argument of the irrelevance of group size, the argument from the principle of need, and the argument of (...) identifiability. It is argued that all of these arguments fail to support the conclusion that orphan drugs should be subsidized to a larger extent than treatments for common diseases. The argument of the irrelevance fails to distinguish between directly and indirectly relevant considerations of fairness or justice. The recent attempt to revive the moral relevance of identifiability has provided no novel reasons to think that identifiability is morally relevant in itself or due to considerations of fairness and justice. The argument from the principle of need does not fail due to any inherent flaw in the principle as such. Rather, this principle can be interpreted in different ways, and none of these interpretations support exceptionally advantageous terms economically for treating rare diseases specifically. It is concluded that we are awaiting justice based reasons for the preferential treatment of orphan drugs. (shrink)