A total of 97 people voted for the dissolution, nine against with two abstentions.
The party, known in Russian as Soyuz Pravykh Sil or SPS, was founded in 2001. In late September 2008, it said it would cooperate with other parties to establish a new liberal party likely to be called Pravoye Delo or Right Cause.
The new party, Right Cause, will hold its inaugural congress on November 16. It is to be based on the SPS party, along with the Democratic Party and Civil Force parties, which are also broadly supportive of the Kremlin.
The party's name, charter, emblem and program are expected to be approved by the organizing committee on Sunday.
The Democratic Party and Civil Force also decided to dissolve themselves on Saturday.
The organizers of the new party said in a statement earlier that its principles were "democracy, the free market, the rule of law and the equality of everyone before the law."
The party's three co-chairmen will be Boris Titov, Georgy Bovt and Leonid Gozman, formerly of Civil Force, the Democratic Party and SPS, respectively. The party is expected to take part in the March 2009 regional elections.
