The execution of Juan Raul Garza had been set by a court for Aug. 5, but the president signed an order postponing the administration of lethal chemicals at the U.S. Penitentiary in Terre Haute, Ind., until Dec. 12.
The Justice Department said Mr. Clinton was "thereby providing an opportunity for Mr. Garza to petition under the new regulations."
Garza, 43, was convicted in August 1993 in Brownsville, Texas, for killing three men between April 1990 and January 1991. A 10-count indictment named him as the boss of a drug ring that imported tons of marijuana into the United States between 1983 and 1993. He has lost appeals all the way up to the Supreme Court.
Ten pages of new rules on clemency in death penalty cases were issued Wednesday by the Justice Department.
Mr. Clinton, a death penalty supporter, called for the new guidelines in early July.
The rules provide that inmates under death sentence will be given 120 days notice of their date of execution and give the inmates 30 days from that notice to ask the president to reduce or commute the sentence.
The rules provide an opportunity for the inmate's attorney to make an oral presentation to the Justice Department's pardon attorney.
They also provide a chance for families of the victims, with the assistance of prosecutors in the case, to make their own oral presentation to the pardon attorney.
Debate over the death penalty has entered this year's presidential campaign.
Garza's imminent execution has swung the spotlight on the issue to the Democrats after the issue dogged Republican Gov. George W. Bush earlier in the summer.
Gary Graham, who pleaded guilty to 10 aggravated robberies during a crime spree in 1981, was executed in Texas in June after a series of unsuccessful appeals.
Bush's state has put more people to death in the past two decades than any othera total of 224 inmates. This year, 23 inmates, including Graham, were executed.
Executions, at the rate of nearly one a week, will be held in Texas before Election Day on Nov. 7.
Garza is one of 21 people, including Oklahoma City bomber Timothy McVeigh, on the federal death row at the penitentiary in Terre Haute.
By MICHAEL J. SNIFFEN