A new meeting room for up to ten delegates will be opened, while the lobby area and 53 of the hotel's 184 bedrooms and bathrooms are being refurbished. A steel and glass reception area will also be built.
The hotel's Grosvenor Club wing, located opposite the main part of the hotel, is to be renamed the Grosvenor Townhouse annexe, where the refurbished rooms will be located.
Hilton Edinburgh Grosvenor general manager Steve Hall said: "Edinburgh is one of the world’s most vibrant capital cities and we have great faith in its direction as a centre for business, conventions and tourism.
"With the city having maintained its popularity through the recession, thanks to our excellent conference and events offering, loyal client base and proximity to the EICC, we are able to offer guests an even more enjoyable stay thanks to our refurbishment."
Interior design company Cunningham McLean Partnerships assisted with the project.
The hotel's eight meeting rooms were recently equipped with av equipment including ceiling mounted LCD projectors and screens.