Leahy argued that electronic documents should receive the same level of legal protection as physical documents.
But he predicted that passing the privacy legislation this year will not be easy.
"It is going to be a fight. But I think people are realizing they don't have to give up their ability to use the Internet while at the same time guarding their freedom," Leahy said in a speech at Georgetown University Law Center.
He tried to attach his email privacy measure to a video deregulation bill last year, but Republicans expressed concern that the requirement would hamper police investigations.
In his speech, Leahy also expressed concern about the new search feature Facebook unveiled on Tuesday, saying it will allow users to "check back and find things about everybody."