Death Penalty Reform Act of 2006

Death Penalty Reform Act of 2006 - Amends the federal criminal code to modify substantive law and procedures relating to the death penalty.

Adds certain crimes that result in death, including obstruction of justice, as aggravating factors in death penalty deliberations.

Defines "mentally retarded" for death penalty purposes. Requires a defendant to give notice to the government of any mitigating factors, including mental retardation, which the defendant intends to present in a death penalty proceeding. Grants the government the right to an independent mental health examination of a defendant claiming mental retardation.

Grants the Attorney General regulatory authority over the implementation of the death penalty. Repeals the prohibition against executing a person who is mentally retarded. Grants the government an unlimited right to rehearings of a finding of mental incapacity in death penalty cases.

Requires a court in a death penalty case to: (1) assign a second attorney for the defendant when the government files a notice of intent to seek a sentence of death (currently, assignment is required upon indictment); and (2) permit the government to strike for cause jurors who oppose the death penalty.

Modifies criteria relating to mitigating and aggravating factors in death penalty cases.

Authorizes a court in the sentencing phase of a death penalty case to impanel a jury of less than 12 members upon a finding of good cause.

Amends the Federal Rules of Criminal Procedure to increase the number of alternative jurors and peremptory challenges to such jurors in criminal proceedings.