The U.S. elected its 45th president on Nov. 8.
Coloradans have decided that terminally ill patients should be allowed to end their lives with the assistance of a physician.
The state joins five others, including California, with so-called "death with dignity" laws that grant terminally diagnosed patients the right to take life-ending, doctor-prescribed sleeping medication.
In recent years, Democrats in the state Legislature had attempted to pass legislation allowing for assisted suicide, but were rejected by Republicans in the split Legislature.
Opposition to the measure came mostly from religious groups.
Colorado, which has an electorate that is roughly evenly divided among Republicans, Democrats and unaffiliated voters, has tilted much more liberal in recent years. In 2012, voters approved Amendment 64, which legalized marijuana for recreational use – making Colorado among the first states in the country to do so.
Other measures on the Colorado ballot include raising the minimum wage and universal healthcare.