The International Criminal Court convicted Bemba of murder, rape and pillaging between October 2002 and March 2003, when forces under his command were sent to CAR to quell a coup attempt.
The court found the crimes "to be of serous gravity," noting that some of the rapes were committed "against particularly defenseless victims" and "with particular cruelty."
"The arrest, conviction and sentencing of Jean-Pierre Bemba sends out a strong signal that those who commit crimes under international law will ultimately be held responsible for their crimes, " Amnesty International's Stephen Cockburn said in a statement Tuesday.
"It also sends a clear message that impunity for sexual violence as a tool of war will not be tolerated and makes clear that military commanders must take all necessary steps to prevent their subordinates from committing such heinous acts," said Cockburn, a deputy regional director for west and central Africa.
Bemba led the Movement for the Liberation of the Congo (Mouvement de Libration du Congo) and became one of the Congo's four vice presidents in 2003 as part of that country's transitional government.
Prosecutors say Bemba knew that MLC forces under his authority and control were committing or about to commit war crimes.
More than 5,200 victims were authorized to participate in Bemba's trial and are eligible for reparations.
Bemba was arrested by Belgian authorities in May 2008 and surrendered to the court the next month. He was convicted on March 21 of this year of two counts of crimes against humanity and three counts of war crimes.
He will get credit for the eight years he has already spent behind bars.