Undhad had left BJP just before the 2007 Assembly elections alleging that chief minister Narendra Modi was running the party in a dictatorial manner.
He today joined BJP at its state headquarters here saying "the country is in need of leadership of Narendra Modi".
Undhad hails from numerically and politically strong Leuva Patel community.
The MLA said he was returning to BJP which gave him footing in politics. He contested on Congress ticket in 2007 and 2012 Assembly elections and emerged victorious.
State BJP president R C Faldu, outgoing Rajya Sabha MP Purshottam Rupala and former agriculture minister Dileep Sanghani were present on the occasion.
Earlier, in the day he submitted his resignation to Assembly speaker Vajubhi Vala, which was accepted.
On quitting Congress at this juncture, Undhad said, "I have joined BJP after holding several discussions and deliberations with my supporters and party leaders.However Congress did no injustice to me".
