Speaking to local reporters Wednesday on a trip to Nigeria, the former Democratic president noted that had won his home state of Georgia and his hometown of Plains.
"My children and their spouses are pro-Obama. My grandchildren are also pro-Obama," he said at a press conference, according to the Nigerian newspaper This Day. "As a superdelegate, I would not disclose who I am rooting for, but I leave you to make that guess."
Carter's spokeswoman confirmed the comments.
Asked about Jimmy Carter indicating he would go for Obama, communications director Howard Wolfson said: "Both Senator Clinton and President Clinton have a great deal of respect for President Carter and have enjoyed their relationship with him over the years. And, obviously, he is free to make whatever decision he thinks is appropriate with regard to the presidential choice."
Asked whether there was concern that Carter would be regarded as a "super-superdelegate" in the process, Wolfson said: "He is clearly a distinguished former leader of our party and is a superdelegate. And I'm sure that people will be interested in the choice that he makes. But no, nothing beyond that."
Carter is one of 13 Georgia Democratic superdelegates - elected officials and party elders who have a vote at the national convention this August in Denver and are free to support the candidate of their choice.
Only three of those have not indicated who they support: Carter, state Rep. Jim Marshall, and former Congressman Richard Ray, who is president of the Georgia chapter of the AFL-CIO.
Among those who have committed, Obama holds a 7-3 lead.
Carter was in Nigeria for a ceremony celebrating a reduction in Guinea worm disease in West Africa.