A new poll conducted by the Denver Post shows a majority of voters support the measure.
The results from the Denver Post's poll show the measure is supported by 50 percent of likely voters who were surveyed, whereas 44 percent oppose it. There is a 3.8 percent margin of error on the poll.
The Denver Post polled 695 voters.
Both sides of the debate say Tuesday will be crucial and voters who cast their ballots that day will ultimately decide whether the measure passes.
Similar measures are also being voted on in Washington and Oregon on Tuesday.
The vote in Washington is expected to pass.
(KUSA-TV © 2012 Multimedia Holdings Corporation)