There is clear evidence of increased medical comorbidity and related mortality in people with severe mental illness, despite numerous guidelines for managing medical conditions in this population. This article assesses inequalities in medical treatment and preventive healthcare received by psychiatric patients compared with the general population. It considers whether the medical care provided is adequate and whether published guidelines improve it. Mental health specialists, general practitioners and hospital specialists appear to deliver poorer than average medical care for this vulnerable population. Implementation of physical healthcare guidelines is incomplete and the guidelines must be matched with resources to address this deficit.