The proposed civil unions bill was approved on a 3-2 vote. The majority Democrats voted "aye," while both Republicans on the panel voted "no."
Testimony was emotional, with Denver Democrat Lucia Guzman pointing out that the measure may give people who have felt the need to hide their sexual preference the courage to be open about it.
"There are those here today who spent years hiding, hiding the truth from their parents, friends, bosses, even hiding from themselves," she said.
Representatives of social conservative groups objected to the bill, as they did when a similar measure was considered in 2011 and 2012.
This year's bill is somewhat wider in scope than the version that would have made it to Gov. John Hickenlooper's desk last year if the then-majority Republicans in the House of Representatives had not killed it with a parliamentary maneuver.
In the 2012 version charities affiliated with the Catholic church would have been exempt from a provision that forbids discrimination against gay people who wish to adopt a child. This year, sponsoring Sen. Pat Steadman, D-Denver, did not include that language.
Among the witnesses testifying in support of the bill were Denver mayor Michael Hancock.
Hickenlooper has indicated that he will sign SB 11. A tweet in his name that was posted Wednesday reiterated that promise.
The bill will next be considered by the Senate Appropriations Committee.