The Congress retained the Mandi Lok Sabha seat with candidate Pratibha Singh winning the bypoll by a margin of over 1.36 lakh votes on Sunday.
Pratibha Singh, wife of chief minister Virbhadra Singh, polled 3.53 lakh votes (60.67%), while her nearest rival and BJP candidate Jairam Thakur got 2.17 lakh (37.24%) votes.
Earlier, this seat was represented by Virbhadra Singh, who resigned following his election to the state assembly in December 2012.
Nearly 53% of the 11,13,938 electors exercised their franchise in the two phases of voting held on June 23 and 27.
Four candidates were in fray for the Mandi byelection. Lawan Thakur of Prism party received 5,932 votes and Independent candidate Subhash Mohan Snehi got 6,057 votes.
However, Thakur received 2,556 more votes than the Congress candidate in his home segment Seraj.
The counting for 1,921 booths of the whole parliamentary constituency began at 8am under tight security in the presence of observers deputed by the Election Commission of India.
While election in 16 assembly segments under Mandi parliamentary constituency was held on June 23, the natural calamity in Kinnaur district forced postponement of election to June 27 with re-poll in one booth of Kinnaur segment was held on June 29.
Pratibha Singh had defeated BJP rebel Maheshwar Singh - who in February 2012 had launched a new political outfit Himachal Lokhit Party - by 66,566 votes in 2004.
She had, however, lost to the four-time MP Maheshwar Singh in 1999 by over 1.31 lakh votes.
The Mandi parliamentary constituency, which includes Kullu, Mandi and some areas of Chamba and Shimla districts, besides the tribal-dominated assembly constituencies of Kinnaur and Lahaul and Spiti, is the second largest constituency in the country after Barmer in Rajasthan.
Speaking to mediapersons here, Pratibha Singh expressed gratitude to the voters and said that the overall development of the state during the Congress regime was the main factor behind the party's win. She also thanked women voters for her unprecedented victory.
She said she would raise the issues of welfare of the people in the state in Parliament and assured the people of speedy development works in the constituency and the state.
Meanwhile, BJP candidate Jairam Thakur accepted the defeat, but added that the government misused its power and machinery to ensure win of the chief minister's wife.
He said the government, including bureaucrats, had put indirect pressure on government employees to vote in favour of the Congress because the prestige of chief minister Virbhadra Singh was at stake and he used every possible way to win the election.