Falkirk MP Eric Joyce has pleaded guilty to four counts of assault in a House of Commons bar.
Joyce admitted the charges at Westminster magistrates court after earlier claiming that he would continue as an MP until the general election.
A window was smashed in the Strangers' Bar in Westminster in the fracas, in which a conservative MP was punched and headbutted by Joyce, 51.
Before appearing at court, he told the Daily Record: "I won't be standing at the next general election but until then I will carry on doing for my constituents what I do at the moment.
"What hasn't been written about is that every year thousands of people come through my constituency office looking for help.
"That flow has continued as normal in the last couple of weeks and I wouldn't expect that to change."
Parliamentary rules allow an MP to remain in their seat if they are charged with a criminal offence so long as they are given a sentence of less than 12 months in jail.
Joyce has also denied claims that he had a fling with a 17-year-old during the run-up to the May 2010 general election.
Meg Lauder, 19, told the Scottish Sun that Joyce kissed her and portrayed himself as a "sex bomb". Joyce dismissed the claims as "simply not true".