In his first public comments on the matter, Mr Obama told a White House news conference that, from what he has seen, no classified information was disclosed which would harm national security.
The president was speaking five days after Gen Petraeus resigned as head of the Central Intelligence Agency after disclosing that he had an affair with his biographer, Paula Broadwell. Current Afghanistan commander General John Allen has since become embroiled in the growing scandal.
Gen Petraeus resigned as head of the CIA on Friday after admitting an extramarital affair with Ms Broadwell. He had been set to give evidence to Congress this week on the September 11 attack on the US Consulate in Benghazi, Libya, in which the US ambassador was killed.
Gen Petraeus has indicated his willingness to testify, the head of the Senate Intelligence Committee, Dianne Feinstein, said today. No date for the testimony has been set, and Ms Feinstein said it would be limited to the Benghazi attacks.
Gen Petraeus, 60, whose highly respected career as the top US commander in Iraq and Afghanistan led some to speculate on a run for president, has expressed regret over the affair with Ms Broadwell.]
US officials say Ms Broadwell, 40, sent harassing, anonymous emails to a woman she apparently saw as a rival for Gen Petraeus's affections. That woman, Jill Kelley, in turn traded sometimes flirtatious email messages with Gen Allen, possible evidence of another inappropriate relationship.
Mr Obama said he did not want to comment on the specifics of the investigation.
He had hoped to use Wednesday's news conference, his first since his re-election, to build support for his economic proposals heading into negotiations with polticians on the so-called fiscal cliff - the year-end, economy-jarring expiry of tax cuts Americans have enjoyed for a decade, combined with automatic across-the-board reductions in spending for the military and domestic programmes.
But the scandal threatens to overshadow the president's economic agenda this week, derail plans for a smooth transition in his national security team and complicate war planning during a critical time in the Afghanistan war effort.