The former Fianna Fáil TD, deputy leader and matriarch of the Lenihan political dynasty was 87 years old.
She had been in ill health in recent years.
Ms O’Rourke maintained a high profile beyond her political career, with TV and radio appearances.
She became a much loved character, nicknamed fondly as ‘Mammy O’Rourke’.
Mary O’Rourke served in the Dáil, Seanad and as a minister for three taoisigh
Throughout her career, she was an outspoken figure, never afraid to express strong opinions.
She was a member of the Oireachtas for nearly 30 years, serving as a senator and TD for Longford-Westmeath and Westmeath.
She was one of five members of her family have served in the Dáil. Her late father Paddy Lenihan, her later brother Brian Lenihan Snr, who was tánaiste and a presidential election candidate, her late nephew Brian Lenihan Jnr, who was minister for finance, and her nephew Conor, who was a junior minister.
And her son, Aengus O’Rourke, is also active in politics and is a member of Westmeath County Council.
Her other son, Feargal O’Rourke, is currently chair of the IDA and was a managing partner of PWC Ireland, making a significant contribution to tax incentives for US multinationals.
During her career, Ms O’Rourke served as ministers for education, heath public enterprise.
She served in the cabinets of taoisigh, Charlie Haughey and Bertie Ahern, and was a junior minister under Albert Reynolds.
She was a TD for almost a quarter of a century, from 1982 to 2002 and again from 2007 to 2011.
She had two stints in the Seanad from 1981 to 1982 and 2002 to 2007, serving as leader of the Seanad.
Ms O’Rourke is predeceased by her beloved husband, Enda, who passed away in 2001.
