Thousands of people are expected in Sheffield as the city plays host to the country's largest disability multi sport event.
The Great Britain Special Olympics will see about 2,600 athletes with learning disabilities compete in 20 sports over four days.
International athletes will parade in the opening ceremony at Bramall Lane football stadium from 17:00 BST.
Spandau Ballet's Tony Hadley is headlining at the ceremony.
The Special Olympics - for people with a variety of intellectual (learning) disabilities - include athletics at the English Institute of Sport, swimming at Pond's Forge international pool, torch relay at Weston Park, and football at Bramall Lane stadium.
Sheffield City Council's deputy leader Olivia Blake said it was a "huge operation" with fringe events across the city.
"We were really keen to bid for the Special Olympics in Sheffield again and we're really proud to be hosting it. Sheffield is an inclusive city with fantastic top-class sporting facilities."
Events manager Gary Clifton, who worked at the event when it was last held in Sheffield in 1993, said logistics were planned meticulously to accommodate athletes, carers and 1,000 volunteers.
He said it would leave a "legacy" for the city.
Adam Cowlishaw from Sheffield, who is competing in the games on the Yorkshire and Humber football team, said: "I'm very excited, I can't wait. It's a dream come true."
Athletes and carers will stay at the University of Sheffield's Endcliffe Village.
Scotland has sent about 500 athletes to the games.