The elections department released a tabulation showing that among the 60,678 residents who voted by mail or at early-voting sites, some 57 percent opposed the expenditure, The Miami Herald reported Wednesday.
The vote tally revealed that 34,780 ballots were cast against the project while 25,898, or 43 percent, favored the expenditure.
A countywide vote on modernization of the Sun Life Stadium had been scheduled for Tuesday but the referendum needed approval from Florida lawmakers. They ended their annual session without passing the Dolphins-backed legislation.
At the time the referendum was canceled the Dolphins were foundering at the polls but a team spokesman dismissed any notion the proposal would have failed.
"We are confident the modernization of Sun Life Stadium would have prevailed," spokesman Erick Jotkoff said in an email.
The National Football League team spent nearly $10 million on the referendum. The county required a $4.8 million nonrefundable payment for election costs while the team spent another $4.5 million on a political campaign to lure voters to the polls.