Gates has spent the past few years spreading his wealth and now he is spreading his message of giving.
"Are the brightest minds working on the hardest problems? I think the answer is probably not. I think we can do better on it," Gates said.
This is Gates' first tour of university across the country since transitioning full time to his foundation. Berkeley was the first stop.
Gates talked about the inequities in poor countries -- health, food, education.
"If you improve education levels, economic success comes," he said.
One of the greatest achievements of the Bill and Melinda Gates Foundation has been the delivery of vaccines to poor nations.
Gates, acknowledges these are tough time for students hoping to find work, but stressed the nonprofit sector has plenty of openings.
The mind behind Microsoft told students why he took on this second career as a full time philanthropist.
"I had a view that giving that to your children is no favor to them or society," Gates said.
"It's very frustrating because we may be from the upper middle class, but you don't have people doing anything for the poor and the thing he is doing, it just really makes you feel there is hope, you know," Cal student Megha Lohia said.
"It was really inspiring trying to figure out exactly how you can help the world and how to reach out to different people," student Nupur Dokras said.
Gates also toured Stanford University Monday and will deliver his giving back message to students at the University of Chicago, Harvard and MIT.