They will represent a majority of the delegates the state will send to the convention at the Quicken Loans Arena in Cleveland, Ohio, from July 18 to 21, CBS News reported on Saturday.
Slates loyal to Cruz won every assembly in Colorado's seven congressional districts, which began on April 2 and culminated on Friday with 12 delegates selected. The Texas senator is well-positioned to pad his total Saturday, when 13 more delegates will be chosen at Colorado Republicans' state convention.
The result shows how Cruz's superior organisation has helped him as he tries to catch up with front-runner Donald Trump. While Cruz's campaign spent months recruiting slates of delegates and securing pledges, Trump only this week hired a Colorado state director.
Two candidates Trump's campaign told backers to support in one district were not even on the ballot.
The Trump campaign said it was not worried and had always expected to fare poorly in Colorado because its assembly process is dominated by party insiders.
"If we had a primary, yes, we would have done very well here," said Trump senior adviser Alan Cobb.
As of now, Trump is leading the Republican race with 746 votes, Cruz in second position with 525 and John Kasich in third with 145. (IANS)