The announcement has been praised by Jewish groups who want to find out the truth about any collaboration between the Vatican and Nazis.
Some claim Pope Pius XII did not do enough to stop the Holocaust and he's been referred to as 'Hitler's Pope'.
Speaking to newspaper Yedioth Ahronot Francis said the only reason the archives hadn't already been released was an agreement between The Vatican and Italy.
"But because of the time that has passed since World War Two, I see no problem with opening the archives the moment we sort out the legal and bureaucratic matters," he said.
He added that he had concerns about what was being said about his predecessor.
"One thing worries me – the image of Pope Pius XII. Pope Pius XII has been accused of all sorts of things, including having been aware of the extermination of the Jews and doing nothing. I'm not saying he didn't make mistakes. He made a few. I get things wrong often too.
"During the Holocaust, Pius gave refuge to many Jews in monasteries in Italy. In the pope's bed at Castel Gandolfo, 42 children were born to couples who found refuge there from the Nazis. These are things that people don't know.
"When Pius XII died, [former Israeli premier] Golda Meir sent a letter that read: 'We share in the pain of humanity. When the Holocaust befell our people, the pope spoke out for the victims.'"
"When you interpret history, you need to do so from the way of thinking of the time in question. I can't judge historical events in modern-day terms. It doesn't work. I'll never get to the truth like that.
"Did Pius XII remain silent in the face of the extermination of the Jews? Did he say all he should have said? We will have to open the archives to know exactly what happened. But to judge the actions, we will also need to understand the circumstances under which he was acting.
"Perhaps it was better for him to remain silent because had he spoken, more Jews would have been murdered? Or maybe the other way around? I don't want to sound petty, but it really gets my goat when I see that everyone is against the Church, against Pius XII – all those detractors.
"And what about the Allies during the war? After all, they were well aware of what was going on in the death camps and they were very familiar with the railroad tracks that led Jews to Auschwitz. They had aerial photographs. And they didn't bomb those tracks. I'll leave that question hanging in the air, and say only that one needs to be very fair in these things."