Hickenlooper made his statement at a news conference where dozens of Colorado business and community leaders stood behind him.
"It is clear these initiatives will kill jobs and damage our state's economy," Hickenlooper said. "These measures risk thousands of jobs, billions of dollars in investment, and millions of dollars in tax revenue."
Mara Sheldon, a spokeswoman for Coloradans for Safe and Clean Energy, the committee sponsoring the initiatives, said the aim "isn't to stop drilling, but create some balance."
"Do we want drilling going on next to homes and schools?" Sheldon said. "That is the question voters are being asked."
The governor tried to negotiate a compromise bill that would have addressed local concerns and removed the initiatives from the ballot.
U.S. Rep. Jared Polis, D-Boulder, is backing the two measures, and he had also said he supported a compromise.
On Wednesday, Hickenlooper announced that a broad compromise bill couldn't be reached.
