Benedict said Pius showed "courageous and paternal dedication"
Pope Benedict XVI has defended the actions of predecessor Pius XII during World War II, saying the pontiff spared no effort to try to save Jews.
Pius XII has long been accused by Jewish groups and scholars of turning a blind eye to the fate of the Jews.
Pope Benedict said that Pius had intervened directly and indirectly but often had to be "secret and silent" given the circumstances.
Pope Benedict said he wanted prejudice against Pius to be overcome.
Analysts say this was one of the strongest Vatican defences yet of Pius's role.
Pope Benedict was speaking at a meeting with the US-based interfaith group, the Pave the Way Foundation, at his summer residence in Castel Gandolfo.
He said Pius showed "courageous and paternal dedication" in trying to save Jews.
Pope Benedict said: "Wherever possible he spared no effort in intervening in their favour either directly or through instructions given to other individuals or to institutions of the Catholic Church.
Pope Benedict said the interventions were "made secretly and silently, precisely because, given the concrete situation of that difficult historical moment, only in this way was it possible to avoid the worst and save the greatest number of Jews".
Pius was the pontiff from 1939 to 1958 and the Vatican has begun his beatification process.
Many Jewish groups criticised him for not speaking out against the Nazis, who killed six million Jews.
Material at the Yad Vashem, the Holocaust memorial in Jerusalem, talks of Pius's "neutral" position.