The former sailor admitted killing 52 people, including 10 children in villages across Ukraine, most of them in a three-month spree.
Judge Dmytro Lypsky told the court: "In line with Ukraine'scriminal code ... Onoprienko is sentenced to the death penalty by shooting."
The five presiding judges gave their verdict at the end of a four-month trial on the man who could be one of the world's worst-ever mass murderers.
Onoprienko, 39, stood head bent, staring at the floor of the locked metal cage that was being used as a dock, as the sentence was announced.
It took three hours to read out the details of the murders and announce the verdict.
'Devil'
During the trial, in his home town of Zhytomyr, he described himself as the Devil and boasted of being the world's best serial killer.
He has expressed no remorse and has claimed that a higher force drove him to commit his crimes.
The death sentence ruling will put Ukraine in an awkward position.
Under its obligations as a Council of Europe member, it is committed to abolishing capital punishment.
But both the public and politicians say the Onoprienko case should be an exception.
Country profiles
The lives changed by Onoprienko
(23 Nov 98 | From Our Own Correspondent)
'Terminator' in the dock
(23 Nov 98 | Europe)
Ukrainian Ministry of Internal Affairs
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