The number of states legalizing medical marijuana is increasing. Medical marijuana is possibly effective therapy for HIV-associated sensory neuropathy. Despite legalization at the state level, however, the current and contradictory federal drug enforcement policy creates the risk that physicians who recommend medical marijuana to their patients will lose their ability to prescribe medications. The federal-state tension has legal and ethical implications for neurologists who receive a request for medical marijuana from their patients since neurologists must strive to both relieve suffering and obey relevant laws. Recommendation of medical marijuana by neurologists to their patients is ethically permissible but is not ethically mandatory.