Welcoming him back into the party-fold, state BJP chief Tirath Singh Rawat said Kandari's return would further boost the party's prospects at the hustings.
Kandari said he regretted taking a wrong step by joining the Congress and felt relieved now as he was back in the party he belonged to.
A BJP MLA in Uttar Pradesh and Uttarakhand assemblies for many years, Kandari defected to the Congress in September 2012 after he was denied the BJP ticket for Tehri Lok Sabha bypoll.
Last month, the Congress suffered a jolt ahead of Lok Sabha elections when its sitting MP from Pauri Lok Sabha seat Satpal Maharaj defected to the BJP.
Polling to five Lok Sabha seats of Uttarakhand is slated for May 7.