Syrian President Bashar al-Assad arrived in Riyadh on Sunday to discuss with Saudi King Abdullah regional developments in Lebanon, Iraq and Iran, dpa reported.
Sources across the region have said that last week's controversial visit to Lebanon by Iranian President Mahmoud Ahmadinejad would top the agenda of the meeting.
It is al-Assad's second visit to the kingdom since the 2005 assassination of former Lebanese prime minister Rafiq Hariri, who had close financial and political ties to Saudi Arabia.
Relations between Damascus and Riyadh were strained after Hariri's son, Saad - the current Lebanese premier - initially blamed Syria for his father's killing.
But diplomatic ties between Syria and Arab states have improved in recent years. Last month, the Lebanese prime minister visited Syria and was quoted in regional papers as saying he had unfairly rushed to accuse Damascus of assassinating his father.
This time a year ago, King Abdullah had made a landmark visit to Damascus, in what was widely seen as a turning point for better relations between the two nations.
Both the Saudi and Syrian leaders visited Beirut a few months ago to hold talks with Lebanese politicians amid concerns that sectarian rifts could widen ahead of a United Nations tribunal's findings in the Hariri assassination.
An initial UN inquiry had led to charges against four pro-Syrian officials in Lebanon, but they were released due to lack of evidence after serving four years in jail.