The decision to expel Jaswant Singh, 76, for six years was taken by BJP President Rajnath Singh, a party statement said.
The party expelled another rebel leader Subhash Maharia, former union minister, who is contesting as an independent in Sikar constituency, also in Rajasthan, against BJP's official nominee.
Jaswant Singh is contesting as an independent against the party's official candidate Sonaram Choudhary who had recently joined BJP after switching over from Coingress.
The party statement said the action was taken against Singh, former External Affairs and Finance Minister, and Maharia as the BJP constitution does not allow partymen to contest independents against its official candidates.
Having been refused nomination, Singh had attacked the party leadership the BJP leadership.
This is the second time in five years that Jaswant Singh was expelled from BJP. In 2009, he had been expelled for his controversial book praising Pakistan founder Mohammed Ali Jinnah. However, he was taken back in the party-fold in June 2010.