Democratic Rep. Steve Lebsock was not present when lawmakers voted 52-9 on Friday to expel him.
Faith Winter and four other women accused Steve Lebsock of harassment and intimidation inside the Colorado General Assembly.
Lebsock, who bitterly contested the claims, said his accusers were lying and accused an independent investigator of bias in concluding the claims.
Steve Lebsock was the third state lawmaker in the US accused of sexual harassment since the #Metoo movement emerged last fall.
The debate over sexual harassment has engulfed both chambers of Colorado's Legislature. Three Republicans in the GOP-led Senate were accused of misconduct.One has stepped down as chair of a committee, while denying wrongdoing.
Also two state lawmakers from California and Arizona were expelled in February over sexual misconduct allegations.
A number of female lawmakers in the US Congress in Washington have also come forward with their own stories of abuse.
In October, The New York Times first reported on multiple allegations of sexual abuse by disgraced Hollywood film producer Harvey Weinstein.
Since then, similar allegations have been leveled against many powerful men in politics, business and entertainment in the US and the UK who have fallen amid allegations of sexual harassment.
