This article reviews newly declassified US intelligence files and other sources, including relevant trial documents, related to the Nazi killing of mentally and physically sick individuals deemed to be of little further use to society. It both supplements and revises existing work on the so-called ‘Euthanasia’ programme at the Kaufbeuren psychiatric institution in Bavaria, and highlights a series of gender issues related to the involvement of women nurses including Catholic nuns, in this institute. In addition, this study not only casts new light on the way in which patients were, from admission onwards, redefined as disposable objects but also emphasises contradictions within the defence case of the defendants.