"We will return to power with more seats. This has happened due to the relentless development work carried out by our government in the last five years," he said.
Voting in Assam was held on March 27, April 1 and April 6.
Sonowal said a large number of people participated in the election process and this reflects that people has reaffirmed their faith in India's inclusive democracy.
"I am grateful to the people of Assam for their wholehearted support to the BJP-led alliance," he said.
He also expressed gratitude to Prime Minister Narendra Modi, Union Home Minister Amit Shah, BJP president J P Nadda, Union ministers, and all BJP leaders and workers who have helped in the entire election process.
A total of over 73 per cent people have participated in the first phase of polling in Assam, over 73 per in the second phase and about 79 per cent in the third phase.
The BJP fought the elections along with the AGP and the UPPL. In 2016, the BJP had won 60 seats, the AGP 14 seats and the then alliance partner BPF 12 seats.
The BPF, this time, is part of the opposition Congress-led ''Mahajoot''.
Meanwhile, Sonowal on Wednesday visited the residences of two CRPF personnel -- Inspector Dilip Kumar Das and Constable Babul Rabha - who were killed by Naxals in Chhattisgarh last week, to express solidarity with the bereaved families.
Das and Rabha hailed from Assam.