Former first lady Lucy Kibaki passed on at the age of 75 while undergoing treatment in London on Tuesday.
She died at the Cromwell Hospital in the South West London where she died while receiving treatment.
It is a high end hospital where the rich and powerful seek treatment; the same hospital where late President Julius Nyerere died from on October 14 in 1999.
The former first lady was transferred to the London hospital after developing respiratory complications.
Mr Gituku Ngari who is the family spokesperson said her earlier admission to Nairobi Hospital was just a routine check up due to her advanced age.
She was last seen in public during the the promulgation of the new Constitution in 2010.
She has since then kept a low profile and was not even present when the former President Mwai Kibaki handed over power to President Uhuru Kenyatta in 2013.
Leaders across Kenya joined Kenyans from all walks of lives in condoling with the family of the former first lady.
President Kenyatta in a statement to newsrooms joined other leaders in condoling with the former President's family for the loss.
He said Ms Kibaki has been unwell for the past one month and has been receiving treatment in Kenya but was subsequently flown to the United Kingdom for specialised treatment.
“Her excellency will be remembered for her immense contribution to the development of this country. Especially notable was her virtues of leadership and commitment to improving the well-being of the ordinary Kenyans in particular her focus on tackling HIV/Aids which will remain an inspiration to many,” said President Kenyatta.
Majority leader Adan Duale through his Twitter account condoled with the former President for the loss of his wife.
“My condolences to former President Mwai Kibaki on the loss of his wife Mama Lucy. May The Almighty give you strength in this trying time,” said Duale on his Twitter message to the family.
Cord Co-Principal Kalonzo Musyoka eulogised the former first lady as a great compatriot who championed for the rights of women and children living with HIV/Aids.
“Death robbed us a great patriot, anti-HIV/Aids campaigner and a girl child education champion,” said Mr Musyoka.
Moses Wetangula urged former President Kibaki to stay strong in the wake of the passing of his wife.
"My family, Bungoma county and the nation at large send sincere condolences to His Excellency Mwai Kibaki and family on the demise of mama Lucy. May her soul rest in peace," said Mr Wetangula.