Prince Harry says he hopes the Invictus Game will “inspire people” affected by mental illness to seek help.
The prince, who founded video games for injured veterans, said at the opening ceremony in Florida that it was “not just physical traumata that our Invictus competitors have overcome”.
This is the second time video games have been operate, after London in 2014.
More than 500 athletes from 14 countries will compete in athletics including athletics, rugby and tennis.
Thousands of people attended the lively welcoming ceremony which included speeches from US First Lady Michelle Obama, Hollywood actor Morgan Freeman and former US President George W Bush. There is likewise performances by British vocalist James Blunt and the soprano Laura Wright.
The BBC’s Aleem Maqbool, who was at the ceremony, said it was “at some times a very emotional event with injured veterans telling their stories” and Prince Harry describing his own experience of 10 years in the British Army.