Colorado is to introduce a limit on ammunition magazines and insist on background checks for all firearms giving it some of the toughest gun laws in the US.
In the wake of the Newtown massacre, which left 20 schoolchildren dead, and under pressure from the White House, the Democratic-controlled house narrowly voted in favour of a number of gun control measures.
The state, which is home to two of America’s worst gun massacres, has been considering tightening up its laws since Columbine in 1999.
Rhonda Fields, a Democrat from Aurora - where 12 people were killed in a shooting in a cinema last year - sponsored the bill limiting the size of ammunition magazines.
He said: "There is a common thread that we see in these massacres.
"They're using high-capacity magazines so they can unleash as many bullets as they can, to kill as many people as they can, in our schools, our theatres and our churches."
Mrs Fields, whose son was shot dead in 2005, added: "Enough is enough. I'm sick and tired of bloodshed."
The House also approved bills requiring background checks on all gun purchases, including those between private sellers and firearms bought online; a ban on concealed firearms at colleges and stadiums; and a requirement that gun purchasers pay for their own background checks.
The ammunition restrictions measure would limit magazines to 15 rounds for firearms, and eight for shotguns.
Colorado now joins California, Massachusetts, Hawaii and New York in a ban on magazines that hold over 10 rounds. New Jersey bans magazines that hold over 15 rounds and Maryland those that hold over 20.
Republicans said that the move restricted Second Amendment rights, which guarantee Americans the right to bear arms, and would not prevent mass shootings like the ones in Aurora and the Connecticut elementary school in December.
"This bill will never keep evil people from doing evil things," said Republican Rep. Jerry Sonnenberg.
Republicans also said students should have the right to defend themselves.
"Do not disarm our young adults in general and our young women in particular on our college campuses in the name of a gun-free zone," Republican Rep. Jim Wilson said.
The debate highlighted a fundamental philosophical difference between many Democrats and Republicans.
The Democrats' leader in the House, Dickey Lee Hullinghorst, said he resented "the implication that unless we all arm ourselves, we will not be adequately protected."
The vote on Colorado's gun control debate is part of the shift in the region's politics to the left, including the legalisation of marijuana in Washington state and Colorado. Washington also upheld the legality of gay marriage in November.