World Health Organization chief Dr. Margaret Chan said the agency was extremely grateful for the help.
"If we are going to go to war with Ebola, we need the resources to fight," she said. "This will make a significant difference in Sierra Leone."
While millions of dollars have already been pledged and countries including Britain and the U.S. have volunteered to build treatment centres, Chan said "human resources are most important," noting a crucial need for experienced doctors and nurses across the region.
"There is not a single bed available for an Ebola patient in the entire country of Liberia," she said, adding that a further 1,500 health workers are desperately needed in West Africa.
Dr. Roberto Morales Ojeda, Cuba's health minister, called on other countries to help.
U.N. Secretary-General Ban Ki-moon welcomed the Cuban announcement and said the African Union "has begun to mobilize medical personnel for the response, and the Government of Ghana has agreed to use Accra as a key hub for flights into and out of Monrovia," U.N spokesman Stephane Dujarric said Friday.
He said the secretary-general is also grateful for U.S. support, including the U.S. Agency for International Development's plans to make an additional $75 million available.
"More than 100 experts, most of them from the U.S. Centers for Disease Control and Prevention, are deployed to the region in an effort to prevent, detect and halt the virus's spread," Dujarric said.
Ebola is believed to have killed more than 2,200 people in West Africa so far, the biggest-ever outbreak of the lethal virus. So far, the death rate is about 50 per cent. Doctors and nurses are at high risk of catching Ebola, spread via the exchange of bodily fluids.
Cuba will be sending experienced doctors, nurses and other scientists to Sierra Leone in early October. They will stay for six months.
Since the 1959 Cuban revolution, the country has dispatched thousands of doctors worldwide to work on issues ranging from maternal health to cataracts.
Cuba's program has been praised for improving health care in countries short on doctors, but also criticized for underpaying the physicians by funneling too much of the compensation for the program to Cuban state coffers.
Associated Press Writers Michael Weissenstein in Havana and Edith M. Lederer at the United Nations contributed to this report.