UC San Diego -- a school for the smart ones, supposedly -- mistakenly congratulated nearly 29,000 applicants on their acceptance, according to university officials.

But on Tuesday, the school's communications office said an e-mail was sent Monday afternoon to all 46,377 students who applied for admission -- including the 29,000 rejects -- welcoming them to the campus.

A half-hour later, school officials said, they realized their mistake. Almost two hours after the first note went out, a second e-mail was sent, apologizing to 28,889 freshmen applicants for the mistake.

"No member of this department is more acutely aware of the emotional roller-coaster that this could cause for our applicants," Assistant Vice Chancellor Mae W. Brown said.

An anonymous parent told the Los Angeles Times it was a "colossal screw-up."

Similar incidents have happened at other schools -- including Cornell in the recent past, the paper reported -- but the UCSD incident was the biggest "screw-up."