The 'First Social Media President' said it "does not make much sense" to put the most private details of his family life on public view. He doesn't want "strangers knowing" their family business, UK's tabloid Mail Online reported.
His elder daughter, Malia, is 13, and just old enough to use Facebook. Her younger sister Sasha is ten. But Obama said he won't consider allowing them to join the site until they are both four years older.
His admission seems somewhat ironic, given that he made full use of Facebook and other websites to encourage the young to vote for him in the presidential election and to raise millions of dollars for his campaign. As a result, he became known as the 'First Social Media President'. His Facebook page which has 24 million 'likes' remains a key part of his ongoing efforts to seek re-election.
One of the many photos on the page shows Mr Obama swimming in the sea with one of his daughters.
In an interview, the President described the thinking behind the Facebook ban as: "Why would we want to have a whole bunch of people who we don't know knowing our business? That doesn't make much sense."
He added: "We'll see how they [his daughters] feel in four years."
But he seemed to have few qualms earlier this week when using Facebook to release the latest official family portrait. The photograph shows the President sitting with First Lady Michelle and their two daughters, all grinning broadly.
It was given the caption: 'The new Obama family portrait!' and has so far drawn 71,000 'likes' and 11,000 comments. It was released to coincide with Christmas, but is not the official Christmas card, which shows an empty room in the White House with the family dog, Bo, lying by the fire.