Speaking in the Senate, he said "some of the allegations against me are simply untrue"
US Senator Al Franken has announced he will resign from the Senate in the coming weeks.
Recent weeks have seen several women accuse Franken - a two-term Minnesota senator and former Saturday Night Live comedian - of inappropriate behaviour and sexual misconduct.
Following an initial allegation that he "forcibly" kissed and apparently groped radio host Leeann Tweeden in 2006, Franken apologised, saying he felt 'disgusted' with himself.
He has, however, denied some of the other allegations made by several women in the wake of the initial claim.
Yesterday, a number of Franken's party colleagues, led by several female senators, publicly called for him to resign.
Speaking in the Senate today, Senator Franken said: "All women deserve to be heard, and their experiences taken seriously.
"I also think [my response] gave some people the wrong impression that I was admitting to doing things that in fact I haven't done. Some of the allegations against me are simply not true. Others I remember very differently.
"I know in my heart that nothing I have done as a senator has brought dishonour on this institution, and I am confident that the Ethics Committee would agree. Nevertheless, today I am announcing that in the coming weeks I will be resigning as a member of the United States Senate."
He added: "This decision is not about me - it's about the people of Minnesota [...] It’s become clear that I can’t both pursue the Ethics Committee process and. at the same time, remain an effective senator for them.”
Washington has been rocked by a number of allegations of inappropriate behaviour by politicians in recent weeks.
Earlier this week, veteran Democratic Congressman John Conyers - who had served in the House of Representatives since 1965, making him the longest-serving politician in the House - announced his decision to immediately resign amid allegations of sexual harassment.
Republicans, meanwhile, have been dealing with the fallout of allegations against Roy Moore, the party's candidate for a vacant Senate seat for Alabama.
The allegations emerged when a woman claimed that Mr Moore 'initiated a sexual encounter' when she was 14 and he was 32.
He has dismissed the allegations as 'completely false'.
Party leaders had initially distanced themselves from Mr Moore and called for him to stand aside, but more recently they have again backed his campaign - with Donald Trump himself voicing his support for the Republican candidate.
Democrats refusal to give even one vote for massive Tax Cuts is why we need Republican Roy Moore to win in Alabama. We need his vote on stopping crime, illegal immigration, Border Wall, Military, Pro Life, V.A., Judges 2nd Amendment and more. No to Jones, a Pelosi/Schumer Puppet!— Donald J. Trump (@realDonaldTrump) December 4, 2017
In his resignation speech today, Senator Franken claimed he was 'aware of the irony' of his resignation in the context of Republican backing for Mr Moore and Donald Trump (who was infamously recorded on video saying he could 'grab women by the p***y').