The study initiated by the NIH after an internal audit indicated possible bias found only about 16 percent of grant applications from black applicants were approved compared with about 29 percent of those from white researchers, The Washington Post reported Thursday.
The study suggests race remains a troubling factor in which researchers receive grants from the main U.S. funding source for biomedical research, its authors said.
"We have a very serious issue," said Donna K. Ginther, director of the University of Kansas Center of Science, Technology and Economic Policy.
"Our research says, 'If you hold everything else constant and the only thing different between these two investigators is the color of their skin, that person is less likely to get funded,'" Ginther said of black grant applicants.
"Science needs to reflect the diversity and power and potential of the population," said Ginther, leader of the study published in the journal Science.
Officials at the $31 billion NIH called the findings alarming.
"This situation is not acceptable," Director Francis S. Collins said. "This data is deeply troubling."
NIH officials said they were taking action to increase the number of black scientists on NIH committees reviewing grant proposals.