The president arrived in Tel Aviv Wednesday. From there, Mr. Obama flew to Jerusalem by helicopter for meetings with Israeli leaders.
During the visit, the president will be discussing Iran's nuclear program and restarting peace talks in the region between Israelis and Palestinians.
At a welcoming ceremony, the president reminded everyone of the importance of the U.S. and Israeli relationship.
"The United States of America stands with the state of Israel because it is in our fundamental national security interest to stand with Israel. It makes us both stronger, it makes us both more prosperous, and it makes the world a better place," said the president, who was warmly greeted by Israeli President Shimon Peres and Prime Minister Benjamin Netanyahu on the tarmac at Tel Aviv's Ben Gurion International Airport.
Seeking to alter a perception among many Israelis that his government has been less supportive of Israel than previous U.S. administrations, Mr. Obama declared the U.S.-Israeli alliance "eternal."
"It is forever," he said to applause as Israeli and U.S. flags.
One other big issue the president will be addressing is the ongoing civil war in neighboring Syria. According to reports, chemical weapons are now being used in that conflict. It is not clear which side used them, but Syria does have a large stockpile of chemical weapons and there are fears that those weapons will not only be used in the fighting there, but could also fall into the hands of terrorists.
However, the U.S. ambassador to Syria said Wednesday that there is no evidence that chemical weapons were used.
Mr. Obama will also be visiting the West Bank and Jordan on his trip.
The Associated Press contributed to this report.