Bloc Québécois Leader Gilles Duceppe is quitting his position after an NDP wave swept through Quebec.
Duceppe lost in his riding of Laurier-Sainte-Marie, falling to the NDP's Hélène Laverdière.
Duceppe told a crowd of supporters that he accepted responsibility for the dismal electoral performance.
"Democracy has spoken, I respect this choice and I assume responsibility for it," Duceppe said.
"I assume responsibility on behalf of the Bloc Québécois. As a result I announce I am leaving my position."
The Bloc Québécois is suffering heavy casualties in Quebec: the party that has dominated the province for almost two decades has been reduced to a handful of seats.
The BQ is leading or elected in three of the province's 75 seats. The party's share of the vote is at roughly 23 per cent.
The Bloc is en route to losing its official party status in the House of Commons. A party needs 12 seats to be recognized as an official party.
Duceppe also pointed out that Quebec voters defeated many Liberals and Conservatives in Quebec.
The BQ leader, however, said that Quebec voters wanted to "try something else."
"Many of those who voted for the NDP wanted to give a final chance to a federalist party in Quebec," Duceppe said.
At the end of his speech, Duceppe told his supporters that they needed to work to become a free country.
BQ held 47 seats at dissolution
When the election was called a month earlier, the Bloc held 47 of the province's 75 seats.
The heavy Bloc losses are coming at the hands of the New Democratic Party. The NDP has garnered 43.6 per cent of the vote so far and that has allowed the party to lead or be elected in 59 seats.
The traditional rivals of the Bloc Québécois, the Liberals and Conservatives, are leading or elected in six seats each.
The Bloc started bleeding support after NDP Leader Jack Layton's strong performance in the English- and French-language leaders' debates.
Shortly after, several public opinion polls suggested the NDP had surged into top spot among Quebec voters of the four political parties.
The BQ appeared on the Canadian political scene in 1993 when Lucien Bouchard led the party to 54 seats. The party had held a majority of Quebec's seats in every election since 1993, from as few as 38 after the 2000 election to 54 seats in 2004.
Duceppe, who was elected in 1990 and has led the party since 1997, was criticized for staying close to Montreal early in the campaign.
The Bloc leader came under fire late in the campaign from members of his own party, when two members wrote an open letter to Quebec voters urging them to vote for the NDP.
Maxime Bellerose, the former president of the Hochelaga riding association, and Benoît Demuy, a one-time political adviser to former Bloc MP Réal Ménard, wrote that they are still convinced sovereignty is the right path for Quebec, but that the struggle needs to happen in Quebec, not in Ottawa.
The letter went on to say that for the first time, social democracy is knocking on the doors of Parliament, and that it would be a shame for Quebecers not to take the opportunity to send MPs to Ottawa who champion the values of mutual help and justice held dearly in Quebec.
In the last week of the campaign, Duceppe leaned on other stalwarts inside the sovereigntist ranks to help him solidify the party's base.
Former Parti Québécois leader Jacques Parizeau called on sovereigntists to vote for Duceppe. And in the final week, Parti Québécois Leader Pauline Marois also hit the hustings with Duceppe in an effort to drum up support for the faltering campaign.
Duceppe said that only his party would stand up for Quebec's interests, and in an effort to beat back the NDP's challenge, he pointed out the federal party supported the 1981 Constitution that does not include Quebec's signature, as well as the Clarity Act.