Punjab Chief Minister Parkash Singh Badal will submit his resignation to the Governor on Sunday following his party's defeat in the assembly election.
The Shiromani Akali Dal, which ruled Punjab for 10 years in alliance with the BJP, trailed at the number three slot in the results as officials counted the votes polled in the 117 seats on Saturday.
The Congress had won on 18 seats and was leading on 61 others by Saturday afternoon.
The Aam Aadmi Party (AAP) won seven seats and was leading on 13 others while the Akali Dal won only one seat and was leading in 12 others.
"I will go to Chandigarh tomorrow and submit my resignation to the Governor," Badal, 89, the oldest Chief Minister in the country, told the media in his village Badal in Muktsar district.
"I am grateful to the people of Punjab for giving me an opportunity to serve them. I am fully satisfied with all the things I was able to do. I will seek forgiveness from people for any mistakes," Badal said.
He said the reasons behind the Akali Dal's defeat would be assessed.