The pope is to become a Twitter user in six languages with the username of @Pontifex from next week.
The Vatican said he will use a question and answer format in his first tweet, focusing on answering questions about faith - in 140 characters.
The pope sent his first tweet last year from a Vatican account to launch the Holy See's news information portal.
The Vatican's communications adviser Greg Burke said @Pontifex was chosen for the pope's personal account because it not only means pope in Latin, but also bridge-builder, suggesting unity. How often will the pope tweet? he said, "as often as he wants."
The Vatican has been increasing its presence in social media to try to spread the faith, particularly among the young. The pope's messages will start on December 12.