Chalk up another gaffe for Joe Biden.

The former vice president was speaking at an event held by the AFL-CIO in Philadelphia on Tuesday when he decided to refer to the time in April when he rallied with striking Stop & Shop workers in Boston.

The thing is, he didn’t quite get the details right, calling it a “Rite Aid strike.”

“When I went up to the Rite Aid strike, I looked out in that parking lot when I was talking with the folks when I was walking the picket line, up in Boston — and what happened? I looked out there, and I’ll bet you 40 percent of the people there were non-union,” Biden said during the Tuesday event, according to a clip posted online.


Biden, who is now considered the front-runner in the Democratic presidential primary, attended the boisterous rally in Boston after some 31,000 Stop & Shop workers, many of them part-timers, went on strike this spring after months of negotiations between the company and their union failed to reach a new contract agreement. (The strike ended 10 days after it started, when an agreement was reached between the two parties.)

During his speech at the rally, Biden told the striking workers that their treatment at the hands of corporate America was “morally wrong.”

“What’s happening here is workers are not being treated across the board with dignity,” Biden said from a podium outside a Stop & Shop at the South Bay Center in Dorchester. “They’re not being treated like they matter.”

Biden appeared about 90 minutes into the event and spoke for about eight minutes, sounding like a candidate for office, ending with a promise that “we will take back this country.”

Larry Edelman of the Globe staff contributed to this report.