The question of whether to provide mental health treatment to prisoners under death sentence who have been judged incompetent for execution presents a powerful ethical dilemma for mental health professionals. Arguments that favor or oppose the provision of treatment are discussed in the context of the nature of the disorder to be treated, the type of treatment to be provided, the goals of treatment, and the relevant legal standard for determining competency for execution. Arguments against treating the incompetent include 1) the need to avoid harming those who are treated, 2) the risk that disclosures in therapy will be used for assessment purposes, 3) the need for paternalism when sufficient harm is necessary, 4) the adverse impact on the clinician, 5) the potential undermining of patient and public perceptions of mental health professionals, and 6) the poor allocation of limited resources. Arguments for treating the incompetent include 1) respect for the wishes of the prisoner, 2) the need to clarify the values underlying the refusal to treat, 3) the low risk of harm from some forms of treatment, and 4) the adverse impact on the milieu stemming from failure to treat. The authors conclude that treating incompetent prisoners may not violate ethical standards under some circumstances, and that some forms of treatment will require the informed consent of the prisoner.Abstract Teaser