Free enterprise has been good to Bill Gates. But today, the Microsoft Corp. chairman will call for a revision of capitalism.

In a speech at the World Economic Forum in Davos, Switzerland, the software tycoon plans to call for a "creative capitalism" that uses market forces to address poor-country needs that he feels are being ignored.

"We have to find a way to make the aspects of capitalism that serve wealthier people serve poorer people as well," Mr. Gates will tell world leaders at the forum, according to a copy of the speech seen by The Wall Street Journal.

Mr. Gates isn't abandoning his belief in capitalism as the best economic system. But in an interview with the Journal last week at his Microsoft office in Redmond, Wash., Mr. Gates said that he has grown impatient with the shortcomings of capitalism. He said he has seen those failings first-hand on trips for Microsoft to places like the South African slum of Soweto, and discussed them with dozens of experts on disease and poverty. He has voraciously read about those failings in books that propose new approaches to narrowing the gap between rich and poor.