They are Cllr David Jones, who was chair of the council in 2001/02, and Cllr Ken Hawkins, the present chair.
Tributes were paid to them at the full council meeting, the last to be held before the elections.
Cllr Jones has represented Denbigh Upper and Henllan for Labour since Denbighshire was created in 1996. He had previously served on Denbigh Borough Council since 1968 and on Glyndwr District Council from 1974.
He was chair in the year that the National Eisteddfod visited Denbigh and was awarded the MBE in recognition of his long and distinguished public service.
Cllr Hawkins has been an Independent member for Ruthin since 1999.
Having previously served as chair of the Licensing Committee and three times as Mayor of Ruthin, he became deputy chair of the council in 2006 and chair in 2007.
Together with the vacancy arising from the death in January of the late Councillor Tom Hodgson, who represented Rhyl South for the Conservative party, this means that there will be at least three new county councillors elected on 1 May.