The foundation says the money will be used by the U.S. Centers for Disease Control and Prevention's Ebola response effort in Guinea, Liberia and Sierra Leone and elsewhere in the world where Ebola is a threat.
The grant follows a $9 million donation made by Microsoft co-founder Paul Allen last month.
Zuckerberg and Chan are making the grant from their fund at the non-profit Silicon Valley Community Foundation.
Also on Tuesday, the World Health Organization said West Africa could see up to 10,000 new Ebola cases a week within two months and confirmed that the death rate in the current outbreak is now 70 per cent.
The disease has killed more than 4,000 people, nearly all of them in West Africa.
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