Olmert, who has been linked with three separate probes involving real estate deals and political appointments, has been accused of taking bribes from an unnamed U.S. businessman, the Ynet news agency said.
According to Ynet, an Israeli-based U.S. businessman handed over large cash bribes to Olmert in Israel and abroad. The businessman is reported to be cooperating with investigators.
All the corruption cases are believed to have taken place before Olmert became prime minister in 2006. The interview, which lasted for around 90 minutes, was held after Israel's attorney general gave police permission to question the premier over a 48-hour period.
In an official statement Olmert's office said the prime minister agreed to "cooperate fully with law enforcement officials, as he has done in the past."
"He is convinced that as the truth will emerge in the framework of the police investigation, the suspicions against him will dissipate," the statement said.
In October last year, the prime minister was questioned in connection with the investigation over political appointments at a state-run enterprise and real estate purchases involving a house in Jerusalem bought at a below-market price in exchange for granting planning permission.
Olmert has also been accused of trying to influence the privatization of the Leumi bank in favor of a friend.
Last year, another famous Israeli politician, ex-president Moshe Katsav was forced to resign following a rape and sexual harassment scandal involving several women.
Russian President Vladimir Putin earlier caused a stir with his off-color comments on the sex scandal during talks with Olmert.
Journalists overheard Putin telling Olmert "say hello to your president - he really surprised us."
