Zainab, 2, is a Miami-area girl, battling Neuroblastoma.
To be a donor, a person must have blood type A or O and they must be missing the same antigen - otherwise Zainab's body will reject the blood.
The blood is even harder to find because the donors must have blood types "O" or "A" and be 100 percent of Indian, Iranian or Pakistani descent, Forbes said.
OneBlood says it's found three matches so far, but the child will need blood transfusions for the foresseable future, which means more donors must be found.
OneBlood is offering to coordinate compatibility testing anywhere in the world.
The tumor inside Zainab Mughal's belly may have been growing for 10 months without anyone knowing. "The possibility of us finding a compatible donor for this little girl within the right ethnic group is less than 4 percent".
Zainab Mughal, two (left and right), from South Florida, was diagnosed with neuroblastoma - a cancer of the nerve cells - in October. "This was the worst thing we were expecting".
Zainab will need up to seven more people to donate throughout the course of her treatment, according to the organization.
Florida-based OneBlood, a nonprofit blood center, has now been conducting an global search to find compatible blood donors.
"We were all crying", Raheel Mughal, the girl's father, said, according to the Miami Herald.
The cancer can spread to tissues beyond the original site, including bone marrow, bone, lymph nodes, liver and skin.
So far, three donors have been located - one of whom lives in the United Kingdom.
Statistically, donors need to be exclusively of Pakistani, Indian or Iranian descent.
Her dad told OneBlood that he, his wife and most of their families donated, but were not a match.
"This is all hands on deck", Bright said in the video.
"What you're doing to save a human life, my daughter's life, is awesome", says Mughal.