The Supreme Court’s death penalty jurisprudence is based in large part on the assumption that jurors can be counted on to apply the law in this area conscientiously and fairly. All our criminal procedure jurisprudence is based in large part on the assumption that prosecutors and judges will act fairly. I believe that these assumptions are based on nothing more than wishful thinking, and that the record of death penalty litigation in the thirty-eight years since the “modern” penalty was approved in Gregg v. Georgia gives the lie to them.This article focuses solely on the role of prosecutors in this process, and the extent to which prosecutorial misconduct has contaminated the entire death penalty process, especially in cases involving defendants with mental disabilities. This is an issue known well to all those who represent such defendants in death penalty cases but, again, there is startlingly little literature on the topic. It is misconduct that is largely hidden and ignored. The article begins with some brief background on issues that relate to the treatment of persons with mental disabilities in the criminal justice system in general. It then discusses prosecutorial misconduct and the outcomes of that misconduct, with special attention to a cohort of appellate decisions in unheralded and rarely (if ever) discussed published cases that, in almost every instance, sanction such misconduct. Next, it demonstrates how some prosecutors purposely flaunt the canons of ethics in the prosecution of defendants with mental disabilities in death penalty cases, and then will discuss some solutions raised by scholars to (at least, partially) cure this problems, and concludes with some modest suggestions of my own.