A 66-pound special cake with a lantern (RJD symbol) designed on it was cut at the party office by the Leader of the Opposition in state assembly Abdul Bari Siddiqui among others.
Prasad's eldest daughter Misa Bharti was also present on the occasion.
The RJD chief is in Delhi and could not attend the celebration.
RJD spokesman Randhir Yadav said that party leaders and workers took a pledge on the occasion to defeat communal forces in the parliamentary elections in 2014 under the leadership of Prasad.