Voting ended on Monday in the Congress presidential poll as senior leaders Mallikarjun Kharge and Shashi Tharoor faced off for the post of AICC chief.
Over 9,000 Pradesh Congress Committee (PCC) delegates form the electoral college to pick the party chief in a secret ballot.
Voting began at 10 am at the AICC headquarters here and at the party's polling booths in state offices across the country.
As voting in the Congress presidential poll got underway, outgoing party chief Sonia Gandhi said she had been waiting for a long time for this day.
Sonia Gandhi and Congress general secretary Priyanka Gandhi Vadra came together at the AICC headquarters and cast their vote.
When asked by reporters about the poll, Sonia Gandhi said, "I have been waiting for a long time for this day."
Later, former prime minister Manmohan Singh also cast his ballot in the poll at the party headquarters where the 68th polling booth for the AICC presidential election was set up.
Veteran Congress leader P Chidambaram was the first to cast his vote at the AICC headquarters here.
Kharge is considered the favourite for his perceived proximity to the Gandhis and backing by senior leaders, even as Tharoor has pitched himself as the candidate of change.
The Congress presidential election is taking place at a time when the party is grappling with major crisis. The results of the poll will be announced on October 19.