It says Mr Kathrada passed away peacefully in Johannesburg's hospital "after a short period of illness, following surgery to the brain".
Along with Nelson Mandela, Mr Kathrada was among eight African National Congress activists sentenced to life imprisonment in 1964.
They were convicted of trying to overthrow the apartheid government.
Mr Kathrada spent 26 years in prison, 18 of which were on the notorious Robben Island.
He was released in 1989, and President Mandela later persuaded him to join him in government.
Ahmed Kathrada left parliament in 1999, but remained active in politics, criticising the recent direction of the ANC and calling on President Jacob Zuma to resign.