Dopamine is a neurotransmitter that has been implicated in processes as diverse as reward, addiction, control of coordinated movement, metabolism and hormonal secretion. Correspondingly, dysregulation of the dopaminergic system has been implicated in diseases such as schizophrenia, Parkinson’s disease, depression, attention deficit hyperactivity disorder, nausea and vomiting, among others. Dopamine’s actions are mediated by a family of five G-protein coupled receptors (GPCRs) (viz. D1, D2, D3, D4 and D5)1. The D2 dopamine receptor (DRD2) is the primary target for both typical2 and atypical3,4 antipsychotic drugs, and for Parkinson’s disease drugs. Unfortunately, many drugs targeting DRD2 frequently cause serious and potentially life-threatening side effects due to promiscuous activities against related receptors4,5. Accordingly, a molecular understanding of DRD2 structure and function could provide a template for the design of safer and more effective medications. Here we provide the crystal structure of DRD2 in complex with the widely prescribed atypical antipsychotic drug risperidone. The DRD2-risperidone structure reveals an unexpected mode of antipsychotic drug binding to dopamine receptors, and illuminates structural determinants essential for the actions of risperidone and related drugs at DRD2.