The meeting, on Sunday, came a day after diplomats said al-Assad had rejected a UN request to interview him about the assassination of former Lebanese prime minister Rafiq al-Hariri.
Prince Saud al-Faisal, the Saudi foreign minister, said during a surprise visit to Damascus earlier on Sunday that the summit between al-Assad and King Abdullah would take place in the Red Sea port city of Jedda and there would be a statement afterwards.
The official Saudi news agency SPA later said Abdullah received al-Assad at a banquet but gave no more details.
Saudi media said the talks in Damascus covered Lebanon. Al-Assad left Saudi Arabia on Sunday evening for Egypt to hold further talks with Hosni Mubarak, the Egyptian president.
Diplomats said on Saturday that al-Assad had rejected a UN request to interview him as part of an inquiry into the 14 February Beirut killing of al-Hariri, who was also a Saudi citizen and close to the Saudi royals.
Syria has strongly denied any role in the truck bombing that killed al-Hariri and 22 others.
Rafiq al-Hariri had good relations
with Abdullah of Saudi Arabia
But a unanimous UN Security Council resolution in October threatens to punish Damascus with unspecified action if it fails to cooperate fully with the inquiry into al-Hariri's death.
Abd al-Halim Khaddam, the former Syrian vice-president, told Arab media late last month that al-Assad had threatened al-Hariri a few months before he was killed.
Saudi Arabia, a key US ally, said in November it had brokered a deal between Damascus and the United Nations to allow the questioning of five Syrian officials in Vienna.
Adel al-Harbi, political editor at the leading Saudi daily al-Riyadh, said Saudi Arabia wanted to find a way for al-Assad to meet the UN team without harming Syria's sovereignty, and to avoid Syria being isolated internationally.
"The anxiety here and in Arab countries is that Syria doesn't cooperate"
Saudi daily Al-Riyadh
"The anxiety here and in Arab countries is that Syria doesn't cooperate. Saudi Arabia is trying to get them to cooperate with the investigation to find the truth," he said.
"An interview which respects Syrian sovereignty does no harm in itself, as long as it is an interview and not questioning," he added.
Diplomats have said that Syria had agreed to allow the investigators to meet Foreign Minister Farouq al-Shara.
Imad Shuaibi, a Syrian political analyst, said: "It seems that there are Saudi and Egyptian efforts to find a comprehensive regional and international agreement regarding the UN request to meet President al-Assad.
"The UN request violated [international] protocol by naming the witnesses whom the commission wanted to meet."
Hosni Mubarak, the Egyptian president, discussed the stand-off with King Abdullah in a stopover in Saudi Arabia last week.
Al-Assad, in an interview with an Egyptian paper, said this week that as president he had international immunity, indicating that UN investigators could not insist on interviewing him.