Bush on Friday was to host a forum on volunteering at Texas A&M University, to be attended by Mr. Obama, who initiated a "United We Serve" call to service in June that culminated in a national day of service on the eighth anniversary of the Sept. 11 terrorist attacks.
The forum is affiliated with the Points of Light Institute, an organization that honors people and groups who participate in community service. Bush created the Daily Point of Light Award in 1989 to honor volunteers. The forum will be held at the A&M campus at College Station, Texas, where Bush's presidential library is located. It was expected to draw students, faculty and Points of Light award winners. Defense Secretary Robert Gates, a former president of the university, was planning to attend as well.
As a candidate, Mr. Obama promised to make a call to public service a cornerstone of his presidency.
On the Martin Luther King Jr. holiday this year, on Jan. 19, the day before Mr. Obama's inauguration, the president-elect, Hollywood stars and thousands of other Americans volunteered across the country.
In April, Mr. Obama signed into law the Edward M. Kennedy Serve America Act, which tripled the size of the AmeriCorps community service program.
And in late June, when Mr. Obama kicked off the call to service program, he and his family worked with other volunteers at Fort McNair in Washington and helped load 15,000 backpacks with books, healthy snacks and toys for children with parents in the armed forces.