Ali Farzat was hospitalized after being forced from his car in Damascus, beaten and dumped on the side of the road, the BBC reported.
Farzat's cartoons have taken aim in the past few months at Syrian President Bashar Assad, who became the country's leader in 2000, succeeding his father.
In a recent cartoon, Farzat depicts a sweating Assad holding a suitcase while trying to get a ride with fallen Libyan leader Moammar Gadhafi, who is driving a getaway car.
Another shows Assad whitewashing the shadow of a security force member while the man is untouched, with a caption reading, "Lifting the emergency law."
Demonstrators have been demanding Assad's ouster since mid-March.
The United Nations says more than 2,200 people have been killed in the Syrian crackdown on anti-government protests.
Since the demonstrations began, human rights groups say, 500 soldiers have also been killed and thousands of people arrested.
Assad had initially allowed Farzat to start an officially sanctioned magazine but soon shut it down.
For four decades, Farzat's drawings have shown brutality, hypocrisy and injustices in the Arab world, the BBC said.
Western nations have urged the United Nations to impose sanctions on Assad's regime.