"I can't give you the exact date, but it's been awhile," he said. He said he thought the last time he spoke with Mr. Obama was at some point in the run up to the 2008 election.
In fact, Mr. Romney has even criticized the president on the campaign trail for not phoning for his advice on health care reform, since he signed into law his own health care plan as Massachusetts governor.
Romney routinely reminded Republican primary voters that the president never asked him for his input, even though the Obama Administration referred to the Romney plan as a model for its own.
"He does me the great favor of saying that I was the inspiration for his plan," he said at a speech this spring in Nevada. "If that's the case, why didn't you call me? Why didn't you ask what was wrong? Why didn't you ask if this was an experiment, what worked and what didn't."
It's unlikely the two rivals discussed "ObamaCare" or "RomneyCare" during their chat, but Romney did tell CBS News that "it was nice to receive his call and I appreciate it."
The call was initiated by the White House to congratulate Romney for securing the Republican nomination.
"We had an exchange of pleasantries and congratulations," Romney said.
The call was described as "brief and cordial" by the Romney campaign, and by both campaigns' accounts, the two wished each other and their families well.
Now with the niceties out of the way, Romney said he is ready for the long, derisive battle ahead.
"I've got broad shoulders. I'm able to handle it," he said.
More from the interview: