May Brown was diagnosed with leukaemia in June last year and has had trouble finding a suitable donor.
Ethnic minority sufferers have a 20% chance of finding a match, whereas white patients have a 60% chance, according to blood cancer charity Anthony Nolan.
It said raising awareness was "vital".
The 22-year-old lives in Weymouth and was told she needed a stem cell transplant after a cycle of chemotherapy did not cure her leukaemia.
Originally from Nigeria, Mrs Brown was told a matching donor had been found last December, but they had then "become unavailable".
She said: "I was devastated, I was shocked because it gave me hope and was snatched away from me."
Anthony Nolan head of register development Ann O'Leary, said: "Growing and diversifying the bone marrow register will mean that people like May can have a second chance at life."
Mrs Brown's plea comes a month after mixed-race blood cancer sufferer Lara Casalotti made a similar appeal for ethnic minority stem cell donors last month.
Mrs Brown added: "I want to do whatever it takes to help raise awareness of the stem cell register.
"Please sign up as a donor and save someone's life."
A mother with leukaemia is urging more black and ethnic minority people to register as stem cell donors as she waits for a transplant.