"As police men and women, always be true promoters of justice and builders of peace," he told officers of the General Inspectorate for Public Security at the Holy See Friday.
The pope told the officers their job was "no simple task" in an area that is a popular spot for tourists and pilgrims, Italy's ANSA news agency reported.
Benedict said the Holy See, the headquarters of the Catholic Church, was not a problem for the city of Rome or for Italy.
"Rather it is a source or richness and a reason to be proud," he said.
N.J. man wakes up from 10-hour sleep with knife in back
Exploding whale video goes viral on Internet