The T4 euthanasia programme within Nazi Germany has been well researched, but much less is known about the extermination of psychiatric patients in Nazi-occupied territories during the same period. In Poland 20,000 mentally ill patients were deliberately killed during the German occupation. This paper traces the history of one psychiatric hospital, Zofiówka, in Otwock, south-east of Warsaw. The hospital once served the Jewish population of Poland and was the largest, most prestigious neuropsychiatric centre in the country. It is now in ruins and said to be haunted by ghosts.