An Taoiseach Leo Varadkar hailed the new facilities at the Curragh as the track's official opening ceremony took place during racing on Sunday.
The centrepiece of the redeveloped racecourse is the Aga Khan Stand, which can cater for up to 6,000 people over four levels, and the Aga Khan himself was on hand to take part in the celebrations.
As well as the stand, the two-year project has yielded refurbished stable yards and parade ring, as well as bespoke facilities including conference capabilities and restaurants. The gallops which are located across the Curragh plains have been upgraded too.
The historic Queen's Room, which was relocated as a standalone feature and reassembled block by block from the old stand, now overlooks the large parade ring.
Varadkar said: "The Curragh has always played an important part in the story of our country and, thanks to this new development, we can be confident that it will play an important role in our future as well.
"The Curragh has gained much more than a new stand. This is a complete redevelopment which will match the best in the world.
"The Government, through Horse Racing Ireland, invested over E36 million in this project, about 40% of the total cost, because we recognised the significance of the Curragh to Irish society.
"I would like to congratulate everyone involved in this two-year project. Irish racing fans have long been able to see some of the very best racehorses in the world compete here. Now, thanks to this development, the facilities on this side of the running rail will match the action on the track."