The former minister, Dula Ram, yesterday accepted membership of the RCP.
Former MLA Ashok Tanwar also quit Congress and joined Rashtriya Janata Party.
Tanwar had contested Assembly elections on Congress ticket in 1998 and won. However, in 2008 he contested as an independent after being denied ticket to contest the polls, but he did not win.
RCP state chief Sanjay Kumar Singh said his party will field candidates for 50 out of 200 Assembly seats.
He said those leaving Congress will be accommodated in the party but not members defecting from BJP.
Assembly elections will be held in Rajasthan on December 1.