A WOMAN has been found hanged in her cell at New Hall Prison, Flockton.
Mary Lucy Walsh, 29, died two weeks after being put on remand for theft.
A Prison Service spokesman said health care staff and paramedics tried resuscitation, but she was pronounced dead.
Ms Walsh, from South Wales, was on remand for theft from Derby Magistrates' Court.
She was alone in a double cell and was not on suicide watch.
The spokesman added: "Every death in custody is a tragedy. We offer our sincere condolences to the family and friends of Ms Walsh."
The police and coroner have been told and there will be an investigation by Prisons Ombudsman Stephen Shaw.
Ms Walsh was the 11th woman to be found dead in a prison cell in England and Wales so far this year.
In total, 55 people have been found dead in prisons this year, compared with 57 at this point in 2003.
Prison Reform Trust director Juliet Lyon said: "Urgent action is needed to address the rising number of deaths of women in custody.
"It is not enough to enable hard-pressed prison staff to respond to women in extreme distress, or to try to turn prisons into hospitals or centres for drug treatment."
She added: "A fundamental question has to be asked about why we are locking up vulnerable women for committing minor offences.
"They are more of a danger to themselves than the public and are in bleak institutions, instead of being provided with the treatment and support they so badly need."