After Governor John Hickenlooper signed an executive order formalizing the casual use of pot into the state's constitution marijuana for recreational use has become legal in Colorado.
Colorado became the second state after Washington to allow pot use without a doctor's recommendation.
Both states, however, prohibit public use of the drug, and commercial sales in Colorado and Washington won't be permitted until after regulations are written next year.
According to the Huffington Post, Hickenlooper tweeted his declaration on Monday and sent an executive order to reporters by email.
Colorado law gave Hickenlooper until Jan. 5 to declare marijuana legal, the report said.
He told reporters on Monday that he saw no reason to wait and did not see any point in letting marijuana become legal without his proclamation, the report added.
"If the voters go out and pass something and they put it in the state constitution, by a significant margin, far be it from myself or any governor to overrule. I mean, this is why it's a democracy, right?" Hickenlooper said.
People above the age of 21 in Colorado may now possess up to an ounce of marijuana, or six plants.