A £3m-PLUS facelift will be carried out at Huddersfield Crematorium and its twin in Dewsbury.
Kirklees Council leaders say the work will provide modern, caring and sensitive services.
Work will include building repairs, new equipment, better and extra parking and upgraded works and landscaping.
Council deputy leader Clr John Smithson said: "The investment over three years will provide long-awaited improvements, modern facilities and quality services."
The spending plans are being unveiled after earlier claims that the two sites would be sold.
Clr Smithson added: "The two crematoria were built in the 1950s and clearly need upgrading to meet today's needs.
"They need improving, both inside the buildings and on their surroundings outside, to provide a modern, attractive and welcoming atmosphere for mourners."
He said work to provide more parking at Huddersfield was nearly finished and further improvements were planned.
More parking at Dewsbury is planned for the coming year.
Clr Smithson said landscape improvements at both crematoria would incorporate arrangements for the burial of cremated remains and give more memorial options for bereaved families.
He added: "This is a very sensitive service, not just during the time when people suffer bereavement, but also over subsequent years when they want to visit memorial grounds to pay their respects.
"It is important the surroundings and memorial grounds are kept to a high standard, and that we provide those features within the grounds."