The US President's former grade three teacher said that Mr Obama - who was known as "Barry" when he attended the Menteng One school in Jakarta - studied the Koran and went to classes on Islam, despite the objections of Ann Dunham, a Catholic.
The teacher's recollections will add to speculation about Mr Obama's links to Islam during his much-anticipated visit to Indonesia, the world's most populous Muslim nation, as part of his ten-day tour of Asia.
His middle name, Hussein, and the fact that his stepfather was a Muslim, have combined to perpetuate rumours about Mr Obama's religious leanings. The number of Americans who think that he is a Muslim has grown since his inauguration to one in five.
Mr Obama moved to Indonesia with his mother and Indonesian stepfather, Lolo Soetoro, when he was 6, and lived there for four years. In his memoirs he recalled his time in the country as the "bounty of a young man's life" and there is affection and pride among Indonesians for the boy who ended up as President of the United States.
The teacher, Effendi, who taught at Menteng One for 29 years, remembers Mr Obama as a "fat, curly-haired, curious boy". The school had an international mix of pupils, including Christians, Hindus, Buddhists and Muslims.
Mr Obama attended classes on Islam while the Christians attended classes on Christianity, said Effendi. Barry, he said, was alone among the pupils in that he insisted on attending both.
"His mother did not like him learning Islam, although his father was a Muslim. Sometimes she came to the school; she was angry with the religious teacher and said 'Why did you teach him the Koran?'" said Effendi. "But he kept going to the classes because he was interested in Islam. He would also join the other pupils for Muslim prayers."
(Anne Barrowclough's report in The Australian)