The fate of the candidates would be decided by 1.3 crore voters in the districts of Lucknow, Varanasi--Prime Minister Narendra Modi's constituency, Allahabad, Mathura, Muzaffarnagar and Etawah among others.
In the state capital, Rajnath Singh cast his vote along with his wife and family members, including son Pankaj Singh who is a legislator.
Mr Sharma voted with his wife in Aishbagh area and said, "The BJP is committed to work for the people and opposition should realise that it was the people's love and trust which ensured the party's victory in the assembly polls. In civic polls too, the party is going to win."
State Election Commissioner SK Agarwal also exercised his franchise and appealed to the people to cast their votes.
"If you want basic amenities in your city, you should come out of your home and vote in large numbers," he said.
Besides them, state ministers Swati Singh, Mohsin Raza and others prominent personalities cast their votes in the first four hours.
The voting would continue till 5 pm.
While the polling for first phase was held on November 22, the last and final phase would be held on November 29.
The counting would be held on December 1.