The Pope is to begin sending Twitter messages using the handle @pontifex as his personal account, the Vatican said.
A spokesman said Pope Benedict XVI wanted to "reach out to everyone" with tweets translated into eight languages.
The first tweet from his account, whose name means both pontiff and builder of bridges, is expected on 12 December.
Last year, the Pope sent his first tweet last year from a Vatican account to launch the Holy See's news information portal.
"We are going to get a spiritual message. The Pope is not going to be walking around with a Blackberry or an iPad and no-one is going to be putting words into the Pope's mouth," Greg Burke, senior media advisor to the Vatican said.
"He will tweet what he wants to tweet," he added, though the leader of the world's 1.2 billion or so Roman Catholics is expected to sign off, rather than write, each individual tweet himself.New platforms
The Vatican said the Pope will be using a question-and-answer format for his first Twitter session, focusing on answering questions about faith in 140 characters.
The Vatican has invited people to start sending in questions ahead of time for the Pope to answer.
The tweets are expected to highlight messages from his weekly general audience, Sunday blessings and homilies on key Church holidays as well as papal reaction to world events.
The BBC's David Willey, in Rome, says that the Vatican has long shown interest in using the latest communications technologies to spread the faith with the inventor of radio, Guglielmo Marconi, setting up Vatican Radio in 1931.
The Catholic church also already uses several social media platforms, including text messages and YouTube, to communicate with young people.
The Vatican's own Twitter account has almost 110,000 followers, though it follows no-one.
Papal aides say the pontiff himself still prefers to communicate in longhand rather than using a computer keyboard.