Yes, despite marijuana recently being made legal in some states, an employer can still fire an employee for testing positive. As seen in a recent Colorado case, this applies even to medical marijuana, though Arizona and Delaware currently have laws protecting medical marijuana users. The main justification for employers freedom to terminate employees who test positive for marijuana is that using and possessing the drug is still illegal under federal law, even though it is legal in some states. For more information on marijuana and employment related drug testing visit our Drug Testing page.