Gratitude is both expected and problematic in live organ donation. Are there grounds to require it, and to forbid access to live donor transplantation to a recipient who fails to signal that he feels any form of gratitude? Recipient gratitude is not currently required for organ donation, but it is expected and may be a moral requirement. Despite this, we argue that making it a condition for live organ transplantation would be unjustified. It would constitute a problematic and disproportionate punishment for perceived immoral behaviour on the part of the recipient. It would also bar the donor from positive aspects of organ donation that remain even in the absence of recipient gratitude. A potential recipient's lack of gratitude should be explored as a possible symptom of other morally problematic issues and integrated into the information provided to the potential donor. Recognition of the donor's gift and gratitude for it may also need to be expressed in part by others. This last aspect is relevant even in cases where the recipient feels and expresses gratitude.