She was 44.
"The Cosby Family thanks many people for their prayers for their beloved and beautiful Ensa," read a statement from the family obtained by CNN.
Renal disease is a condition that impairs kidney function.
Ensa Cosby voiced strong support for her father after he was accused of sexual assault, saying she believed he was innocent.
Last May, Ensa and her sister Erinn released audio statements in support of their famous father.
"I believe that racism has played a big role in all aspects of this scandal," Ensa Cosby wrote.
"My father has been publicly lynched in the media," she said. "My family, my young daughter, my young niece and nephew have had to stand helplessly by and watch the double standards of pretending to protect the rights of some, but ignoring the rights of others and exposing innocent children to such appalling accusations about someone they love dearly and who has been so loving and kind to them is beyond cruel."
The elder Cosby has denied the allegations.
Despite her father's fame, Ensa Cosby led a life away from the spotlight.
She is one of five children born to the superstar actor and his wife, Camille.
The couple's only son, Ennis, was murdered at the age of 27 in 1997 during a failed robbery attempt.
Funeral plans for Ensa have not yet been announced.
CNN's Steve Forest contributed to this story.
Ensa Cosby, who spoke out on behalf of her father, Bill Cosby, before his trial last year on charges of drugging and molesting a woman at his suburban Philadelphia home in 2004, died on Friday in Massachusetts. She was 44.
Andrew Wyatt, a spokesman for Mr. Cosby, said the cause was kidney disease. No other details were provided.
Mr. Cosby owns a home in the western Massachusetts town of Shelburne Falls.
He has pleaded not guilty to the charges and remains free on bail ahead of a retrial scheduled for April 2. His first trial ended last year with a hung jury.
Ensa Cosby and her sister Erinn recorded statements before their father’s first trial that were broadcast on the New York hip hop radio station Power 105. Ensa Cosby maintained that her father was innocent of the charges and that racism had played a role in the scandal.
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“How my father is being punished by a society that still believes black men rape white women but passes off ‘boys will be boys’ when white men are accused,” she said, “and how the politics of our country prove my disgust. My father has been publicly lynched in the media.”
Bill Cosby's daughter Ensa Cosby has passed away at the age of 44.
"The Cosby family thanks many people for their prayers for their beloved and beautiful Ensa, who recently died from renal disease," a Cosby rep tells E! News in a statement.
TMZ reports that Ensa died on Friday, February 23 in Massachusetts.
Ensa had once worked alongside her father Bill in the past, she appeared on The Cosby Show in 1989 as a girl at a party. The season six episode Ensa appeared in was entitled, "I'm 'In' with the 'In' Crowd."
Ensa had been a big supporter of her dad over the years, standing up for him amid his legal battles.
Bill Cosby's daughter has died at the age of 44, just a month before he's due to face a retrial on rape charges.
According to TMZ, Ensa Cosby passed away on Friday in Massachusetts where the family has a home.
Cosby's spokesperson, Andrew Wyatt, said that Ensa's death was the result of kidney disease.
Cosby's daughter was a huge supporter of her father during his sexual assault trial last year saying the accusations were racially-charged.
"I'm a very private person and I've chosen to live my life with my family quietly but for my child, my niece and my nephew, and my father, I can't sit quietly anymore," Ensa said. "The man portrayed in the media today is not who my father is."
She then added that the sexual assault claims had damaged her father's reputation saying, "The accusations against my father have been one sided since the beginning, and when he tried to defend himself he was sued in civil court. I've seen the accusations become more horrific and extreme with time and I have witnessed my father's reputation and legendary work be dismissed without any proof."
Ensa continued, "I strongly believe my father is innocent of the crimes alleged against him and I believe that racism has played a big role in all aspects of this scandal."
She concluded her statement saying Bill had been "lynched in the media" and called the accusations against him "cruel."
Ensa was a yoga instructor in Sherburne Falls near her family's estate; she had also appeared in an episode of The Cosby Show during 1989.
The Cosby Show character Vanessa Huxtable was based on Ensa.
She married her husband Martin McLean in August 2013. She had one child from a previous relationship and McLean had four children.
For the past five years, Ensa and McLean had lived on the family estate. Ensa is the second child of Bill's that has passed away.
In 1997, his son Ennis was murdered in a car-jacking gone wrong in Los Angeles.
Ensa is survived by her husband, her parents Bill and Camille and her siblings Erika, Erinn and Evin.
