"This mistake was inexcusable," MSNBC spokesman Jeremy Gaines said.
It happened during the opening of "Hardball" Monday evening.
Matthews was previewing a story on the controversy over Obama's use of another politician's words, and a picture of bin Laden briefly flashed on the screen beside him with the headline "Words About Words."
The Obama campaign immediately called NBC to complain, and Matthews apologized on the air a few minutes later. When "Hardball" was rerun later that night, a picture of Obama replaced the picture of the terrorist leader.
The mistake was made by someone in the network's graphics department whom MSNBC would not identify. The network did not explain how the mistake was made nor detail the punishment for the employee.
Obama spokesman Tommy Vietor noted the apology and said the campaign had no other comment.
It's hardly the first time the presidential candidate and terrorist leader have been confused in the media. CNN apologized last year for promoting a story on the search for bin Laden with the headline, "Where's Obama?"
One other time, CNN's Alina Cho reported that "Barack Obama's campaign has been dogged by false rumors, among them that Osama is a Muslim, Obama rather."
Even former GOP presidential candidate Mitt Romney misspoke on the campaign trail last October when talking about terrorism.
"Actually, just look at what Osam, uh, Barack Obama said just yesterday," he said.
As long as it's a slip of the tongue, people should just get over it, said Barbara Wallraff, who writes a syndicated column on language.
"Don't we have other things to complain about?" she said.
Wallraff noted how changing one letter can also transform "Bush" to "bust" or "lush." She said the spell-check on one of her computer programs always suggests "Osama" as a substitute when she types "Obama."
It's far different if something like this is done intentionally, she said.
This has been a rough month of apologies at MSNBC. Reporter David Shuster was suspended for two weeks for saying that Hillary Rodham Clinton's campaign had "pimped out" daughter Chelsea by having her make political phone calls. And Matthews apologized last month after suggesting that Clinton's political prominence was due to her husband's infidelities.
