"If I'm elected president, my cabinet--my administration will look like the country. I commit that I will, in fact, appoint a woman to be vice president," Biden said during Sunday night's Democratic debate on CNN. "There are a number of women who are qualified to be president tomorrow. I would pick a woman to be my vice president."
Sanders said he would pick a female vice president "in all likelihood."
He added: "To me, it's not just nominating a woman. It is making sure that we have a progressive woman and there are progressive women out there, so my very strong tendency is to move in that direction."
Neither candidate spoke in further detail about who he would pick as his running mate.
Also Sunday night, Biden repeated a previous pledge to nominate a black woman to the U.S. Supreme Court if given the chance to do so as president.
Both he and Sanders have been under pressure to consider a woman or person of color as a running mate as the once-historically diverse field of Democratic presidential candidates has dwindled to two white men.
The Associated Press contributed to this report.