A new Massachusetts law that has legalized the recreational use of marijuana in the state seeks to control its production and distribution under a system of licenses, regulations and taxes. The law allows for certain amounts of marijuana to be found on a person 21 or older in public and in his/her private home. But how does this affect the rights and obligations of employers? For one, employers are not obligated to permit the use of marijuana during work hours and are free to establish drug-free workplaces and drug testing policies. Use outside of work is more complicated and may change as the law develops, however, the law does not state that an employee cannot be fired or face penalties for testing positive to the substance. This does not mean that an employer might not face legal challenges for denying an employee the right to use marijuana for recreational or medicinal purposes. It is important for employers to evaluate their existing drug-related policies and practices to consider how they may relate to the state’s new laws on marijuana use.