"I would pick a woman to be my vice president," Biden said, while also committing to appoint the first black woman to the Supreme Court.
"My running mate will be a woman," his campaign tweeted moments afterward.
Prior to the debate, Biden had said that he would consider choosing a woman to serve as the vice presidential nominee.
Biden’s rival for the nomination – Sen. Bernie Sanders of Vermont – wouldn’t firmly commit to naming a female as his vice presidential nominee.
Asked by the debate moderators if he’d also choose a woman as his running mate, Sanders answered: “In all likelihood, I will.”
After Sen. Elizabeth Warren of Massachusetts – the last major female Democratic presidential candidate – dropped out of the race earlier this month, there’s been a rising chorus of calls that either Biden or Sanders name a woman as their running mate.
Rep. Tulsi Gabbard of Hawaii remains in the race, but has no realistic chance of winning the nomination.