Patel, who arrived in Rajkot on Thursday by a helicopter from Visavadar, from where he is contesting, went to the polling booth, Sawaswati Sishu Mandir, along with a pilot car to cast his vote.
The GPP chief, known for his strong anti-Narendra Modi stand, meanwhile, said after casting his vote that his party would form a government with an absolute majority. He said a strong anti-incumbency mood was blowing across the state.
Patel, who became the first BJP chief minister of the state in 1995 and pulled out of the party to float the GPP in August, said some power-hungry leaders were projecting misleading pictures but the people of the state wanted a change and the GPP would lead the charge.
Eighty-seven constituencies in Saurashtra and south Gujarat went to the election during the first phase on Thursday and the state unit presidents of the BJP, Congress and the GPP were contesting the polls.