The pop star, 24, has given the money to the radiotherapy department at the Queen Elizabeth Hospital in Bridgetown, which has now been remaned the Clara Braithwaite Centre for Oncology and Nuclear Medicine.
Rihanna and her mother Monica visited the hospital on Saturday and in a statement the star said: “This was my way of giving back to Barbados, in a form of philanthropy, by assisting the Qeh in its continued modernisation program.
“I believe that this will have a huge impact on the people of Barbados. This was all done to save lives or at least extend them.”
She said she had been too busy to shop for the holidays and took to her Twitter page to ask her fans what she should get for her brother.
She wrote: “The most difficult person to buy for is my little brother. He’s getting to an age where toys aren’t fun anymore, any 16-year-olds here? Tweet me!”