Both the Prosecutor General's Office and the defense had appealed the Moscow City Court's verdict earlier.
The prosecution requested a life sentence, and the defense team lodged an appeal against the sentence, saying it was illegal and unfounded.
In August, the Moscow City Court sentenced Pichugin to 24 years in prison for the attempted murder of businessman Andrei Rybin, and the murders of entrepreneur Valentina Korneyeva and the mayor of the Siberian oil town of Neftyugansk, Yury Petukhov.
"The defendant's guilt has been substantiated by criminal case materials and witness testimony," the court said in the verdict, adding that it had been mitigated because Pichugin had underage children.
At the time, Pichugin was already serving a 20-year sentence for two killings and an attempted murder.
A law enforcement source told RIA Novosti earlier that a new investigation has been launched against Pichugin
Anatoly Bashmakov, a representative of the Prosecutor General's Office at the Supreme Court, told RIA Novosti Monday he is satisfied with the court's ruling to revoke the sentence and send the case for retrial.
"The sentence was unjust as too lenient," he said.
But lawyer Georgy Kaganer said his defendant was not involved in the crimes and that his guilt had not been proved. He said his client was put in prison "for only one purpose, to put pressure on Yukos heads."
Mikhail Khodorkovsky, founder of what was once the leading independent oil company in Russia, is serving an eight-year prison term on fraud and tax evasion charges. Leonid Nevzlin, a principal Yukos shareholder, fled the investigation and is now living in Israel.