OBJECTIVE Standardized mortality ratios are twice the population average in the year following a mental health admission, yet there is a relative paucity of research on uptake of general medical care in psychiatric inpatients. METHODS A retrospective database analysis was performed to ascertain the frequency of acute medical care usage by psychiatric inpatients. Data were gathered through a static linkage between anonymized clinical records in a large UK mental health provider and the national hospital activity database (Hospital Episode Statistics) over 1year from 2010 to 2011. RESULTS Over the year, 10.4% of the 8023 psychiatric admission episodes included at least one night in a general hospital during that psychiatric inpatient stay, while 12.0% of psychiatry admission episodes entailed an emergency department (ED) visit. Over the course of the full year, of the 4674 people admitted to the mental health provider at least once, 16.0% were admitted to a general hospital while registered as a mental health inpatient and 18.0% were seen in the ED. Patients were simultaneously registered as occupying beds in both general and psychiatric hospitals for a total of 5163 bed days at a cost of £2.4 million over the year. CONCLUSIONS This large population-based linkage study indicates a high rate of general hospital utilization by psychiatric inpatients in an independent mental health provider. The need for combined, flexible and practical approaches to the medical care of psychiatric inpatients is highlighted to reduce unplanned care and provide treatment in the site best suited to the patient's needs.