Software billionaire Bill Gates announced yesterday that his charitable foundation will spend $200 million to pay for promising but overlooked medical research targeted at diseases most prevalent in poor and underdeveloped countries.

The grants are meant to draw attention and brainpower to diseases such as malaria, tuberculosis, bacterial meningitis and childhood diarrheal illness. Those conditions are responsible for much of the global burden of disease but are relatively rare in industrialized countries, whose health problems set the agenda for the most biomedical research.

"There has got to be, given market signals, systematic underinvestment in research on diseases of people who cannot afford medical treatment. . . . It's just a basic fact that 90 percent of the world's health research spending goes on 10 percent of the problems," Gates said. "So the mismatch, over time, has been a problem."

The $200 million will be disbursed after a committee of scientists from around the world spends about nine months identifying what Gates called the "grand challenges" of global health.

In a telephone news conference with reporters last week, Gates said he hopes the list of a dozen topics ripe for breakthroughs will be analogous to a list of 23 unsolved mathematical problems that a German mathematician named David Hilbert drew up and publicized in 1900. That list is thought to have had a profound effect on the course of mathematical research in the 20th century.

Among the health challenges that might be on the list are: identifying a way to block reactivation of the tuberculosis bacterium, which is harbored by more than a billion people; finding ways to reduce the ability of insects such as mosquitoes to transmit disease-causing viruses and parasites; and identifying novel strategies to deliver vitamins and other "micronutrients" to poorly nourished people, especially children.

"It is highly unlikely the board will identify an idea that has not been thought about previously," said Richard Klausner, the director of global health for the Bill & Melinda Gates Foundation. He added, however, that he expects the board, which will award the grants, will favor some "very high-risk, collaborative approaches" of the sort that neither government agencies nor pharmaceutical companies are likely to underwrite. Novel approaches for preventing or treating AIDS may be on the list, Gates said.

Research into infectious diseases and early childhood health problems are expected to be the main focus of the grants. Obesity, diabetes, cardiovascular disease and tobacco-related illness -- "all emerging as major Third World health problems, but also the objects of much research in rich countries" -- are unlikely to be priorities, he added.

The grants will be administered through the Foundation for the National Institutes of Health, established in 1996. In recent years, the foundation has raised about $17 million to help pay for the sequencing of the mouse genome, and it is currently raising $22 million for a public-and-private initiative seeking to find biological markers that identify people at risk of developing osteoporosis.

The board that will draw up the list of "grand challenges" will be headed by Harold Varmus, former director of NIH, and will include Elias Zerhouni, the current director. Gates, whose foundation spends about $800 million a year on health-related causes, announced the new initiative at the World Economic Forum yesterday in Davos, Switzerland.

Microsoft founder Bill Gates announced yesterday that the Bill & Melinda Gates Foundation would spend $200 million for underfunded medical research. Gates said the money would be aimed at diseases that plague poor countries.