Patients prescribed clozapine have associated physical health risks because of both use of the drug itself and their underlying mental illness. It is therefore important that primary and secondary care work closely together to optimise patient care. Here, the authors describe their audit of patients prescribed clozapine in secondary care to identify whether they were registered on their GP practice's severe mental illness register and whether the practice had a record that they were taking clozapine. Copyright © 2010 Wiley Interface Ltd