The previous record dated back to 2014 when 278 candidates were nominated.
"This reflects the fact that we live in a world where there are a lot of conflicts and where there are also a certain number of processes that are heading in a more positive direction," the head of the Nobel Institute, Olav Njolstad, told AFP.
"Clearly, this has inspired a lot of people to exercise their right to nominate someone," he added.
There were 228 individuals and 148 organisations nominated, the institute said.
The names on the list will remain a tightly-guarded secret for at least 50 years, unless those who nominated them -- lawmakers and cabinet ministers, former laureates, and some university professors, among others -- decide to publicly reveal their candidate.
As a result, known to be on the list are US Republican presidential hopeful Donald Trump, the Colombian peace process negotiators, Pope Francis, German Chancellor Angela Merkel, residents of the Greek islands helping migrants, and US Hollywood actress-activist Susan Sarandon.
The list also includes Congolese gynaecologist Denis Mukwege, Nadia Murad, a Yazidi abducted by IS fighters in August 2014 from her village in Iraq and held for three months as a sex slave, and the Afghan Cycling Federation women's team, nominated by a group of Italian MPs hailing the bicycle as environmental, economic and democratic.
The five-member Nobel Committee which selects the winner held its first meeting on Monday, during which members were able to nominate candidates of their own choice.
The name or names of the laureate -- there can be a maximum of three -- will be announced on October 7.
Last year, the prize went to four Tunisian groups that rescued the country's transition to democracy.