Obama released the news on his Web site early today (Saturday) following widespread media speculation that Biden had been tapped for the role of vice president.
Obama said Biden would bring to the ticket his extensive foreign policy experience, and record of collaborating across party lines, as well as having a direct approach to get jobs done.
Biden, who was elected to the Senate in 1972 at the age of 29, is chairman of the Senate Foreign Relations Committee.
Obama and Biden are expected to appear Saturday at a rally in Springfield, in Obama's home state of Illinois.
The Democratic National Convention begins Monday in Denver, Colorado, while Republicans gather the following week for their four-day convention in St. Paul, Minnesota.
Some information for this report was provided by AFP, AP and Reuters. - Reported by VOA News
Barack Obama's Text Message Below
the text message is out and it's official... Barack Obama has selected Joe Biden to be his running mate!
Please take a minute to share your story with Joe and welcome him into our movement for change. For those of you who are from Delaware and know Joe best, we'd love to hear your experiences as a constituent of Senator Biden's.
We'll make sure to share some of your stories with Senator Biden so he gets a chance to better know the remarkable folks who've built this campaign from the bottom up.
As Senator Obama and Senator Biden head to Denver, your grassroots support is more critical than ever.