Israel often conceals the identities of lottery winners to protect their privacy. The couple wore red masks with the lottery agency's logo at the news conference. The woman also wore a wide-brimmed black sun hat.
"This win is thanks to my wife who pushed me to go check the tickets because otherwise I wouldn't have found it," the man said.
After determining they had a winning ticket, the couple made a late-night visit to a store to see how large the prize would be. The husband said a silence fell over the room as they began counting the number of zeros in the winning payout with the clerk.
"How much did we win, for God's sake?" he said he recalled thinking. "Everyone there was pretty shocked."
The two said they have no idea what to do with their newfound fortune.
The $20 million prize is subject to a 25 percent tax in Israel, the lottery agency said.