Many states, such as Maryland and New Jersey, have enacted laws legalizing medical marijuana and decriminalizing its possession. Additionally, several states, including the District of Columbia, have passed legislation permitting the sale and use of cannabis for recreational purposes. As a result, there may be an influx of tenants seeking approval from their landlords to use marijuana in their rental housing units even in circumstances when the property is explicitly drug-free and smoke-free. These tenants will argue that their medical marijuana usage is legal under state law, or that allowing their use of medical marijuana is a reasonable accommodation under the Fair Housing Act (FHA). Nevertheless, landlords may restrict marijuana use—medical or otherwise—on their properties. Despite any legalization at the state level, cannabis remains a controlled substance under federal law. Under the FHA, a landlord is required to make reasonable accommodations in rules, policies, practices, or services, when such accommodations may be necessary to afford a tenant with equal opportunity to use and enjoy their dwelling. The FHA, however, only requires landlords to make accommodations for ‘disabled’ tenants, and the FHA specifically excludes people with current, illegal uses of controlled substances from its ‘disabled’ definition. Because marijuana, for any use, remains illegal under federal law, a tenant is not entitled to use medical marijuana on a rental property as a reasonable accommodation, even if they lawfully possess a medical marijuana card under their state law. To date, federal law and the FHA has not made an exception for the use of medical marijuana. Additionally, under the FHA, a landlord may deny requests for an accommodation if such accommodation would fundamentally alter the nature of the housing provider’s operations. For example, although medical marijuana use may be legal at the state level, the Federal Controlled Substance Act (FCSA) prohibits the use or possession of marijuana. Accommodating medical marijuana usage, therefore, amounts to a landlord permitting the violation of federal criminal laws on its rental property. Also, many landlords impose drug-free and smoke-free policies to prevent substantial and serious threats of danger to the life, health and safety of all occupants of rental property. Permitting a tenant to use medical marijuana on the rental property may endanger the health and safety of others causing an undue hardship. As the debate on the legalization of marijuana continues and the legislation and case law on medical marijuana use in rental housing expands, it is too early to conclude that it will always be lawful for landlords to deny medical marijuana use accommodation requests. In the meantime, landlords should consider revising their leases to include language prohibiting all tenants from using marijuana on the rental property, regardless of whether the tenant is lawfully certified by the state to use medical marijuana. Additionally, landlords should maintain a clear policy detailing how tenants may submit requests for accommodations and should always consult with an attorney before granting or denying such requests—even those that include uses for controlled substances.