The winning Lotto numbers were announced as 9, 11, 39, 44, 49 and 86, with the bonus number 47.
The winning ticket was bought in the Corona bar in Veduggio con Colzano, about 30 km outside the northern city of Milan.
Shortly after the announcement, the bar was overrun with people who had come to celebrate the jackpot.
The winner's identity remained unclear, but barman Lorenzo Jerano, 28, said he or she was likely to be a neighbour.
"It's only local people who play here," he said, adding "I hope it's someone who needs money. If it's someone who's already rolling in it, I hope he gives a lot of it away to charity."
"I hope it's someone who needs money. If it's someone who's already rolling in it, I hope he gives a lot of it away to charity."
--Barman Lorenzo Jerano
The "Superenalotto" jackpot reached its unprecedented high after 44 consecutive rounds since February had failed to draw a winner -- the longest turnover period in the six years since it became a twice-weekly event.
The prospect of a record payout had drawn punters in their hundreds of thousands across Italy -- the Corona bar alone sold 1,500 tickets. Even tourists from Germany and Austria crossed the border to play.
Earlier on Wednesday, tens of thousands of people had laid siege to bars and restaurants in a last-minute rush for tickets.