A task force convened by Colorado’s governor to address issues arising out of Amendment 64, a state constitutional amendment that purports to legalize the recreational use of marijuana by adults in Colorado, recommended that “employers may maintain, create new, or modify existing policies in response to the passage” of the law. The recommendation is a preliminary signal that even as the state liberalizes its marijuana laws concerning medical and recreational use, employers still may regulate all marijuana use, even off-duty and off-premises use, by their employees. Although the task force’s recommendation lacks the force of law, its implications for employers are important. Employers should review and update their drug policies to ensure that employees understand that they apply to the use of all drugs that are illegal under state or federal law, including marijuana. Employers in others states seeking to enact liberalized marijuana laws should work vigilantly to ensure that those measures include strong, clear protections so they will be able to maintain, change, and enforce their drug-free workplace, zero-tolerance, random drug testing, and related policies.