The US, he declared, wants to "step up our game" in a region that is home to six of the world's 10 fastest growing economies.
The president was welcomed in Tanzania by the largest crowds of his weeklong trip to the continent where his family ties run deep.
Thousands of people lined the streets as his motorcade sped through this city on the shores of the Indian Ocean, some wearing shirts and traditional khanga wraps bearing Obama's image.
Throughout his three-country trip, Obama has touted a new model for US partnership with Africa, one based not just on aid and assistance, but also on trade.
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While the US has long been a leader in foreign aid to Africa, China has surpassed America as sub-Saharan Africa's largest trading partner.
Countries like India, Turkey and Brazil also are increasing their presence on the continent.
"I see Africa as the world's next major economic success story," Obama told US and African business leaders today. He spoke following a private meeting with top executives, including representatives from Coca Cola, Microsoft and General Electric.
But he also challenged African leaders to pick their international partners carefully, saying they should push back against countries that bring in their own workers or mine Africa's natural resources but handle the production outside the continent, all criticisms that have been levied against China.
Seeking to draw a contrast with Beijing, the president said his administration's goal was "for Africa to build Africa for Africans," and for the US to be a partner in that process.