“Raef Badawi has been sentenced to seven years in jail and 600 lashes," lawyer Waleed Abualkhair wrote on his Twitter account.
The judge also ordered the closure of the website of the Saudi Liberal Network.
Badawi, 35, was arrested in June last year in the Red Sea city of Jeddah for unknown reasons.
The network that he co-founded with female rights activist Suad al-Shammari, had announced May 7, 2012 a "day of liberalism" in the Muslim kingdom.
More than 40,000 political prisoners, mostly prisoners of conscience, are in jails across Saudi Arabia.
According to the activists, most of the detained political thinkers are being held by the government without trial or legitimate charges and have been arrested for merely looking suspicious.
In Saudi Arabia, protests and political gatherings of any kind are prohibited.
Since February 2011, protesters have held demonstrations on an almost regular basis in Saudi Arabia, mainly in Qatif and Awamiyah, primarily calling for the release of all political prisoners, freedom of expression and assembly, and an end to widespread discrimination.
MRKD/NJF