OBJECTIVE: Abuse by a spouse or a partner is an increasing social problem that has economic as well as clinical consequences. This study estimates the cost of hospital care for medical problems resulting from spousal or partner abuse. METHODS: Admissions related to spousal or partner abuse and reason for admission were identified by ICD-9 diagnosis and E-codes. Inpatient hospital costs were estimated based on data from 5 US states from years 1997-2000. Cost estimates include all accommodation, ancillary and physician services. National fee schedules were also used. Cost estimates are reported in 2002 US$. Charges were adjusted by means of a cost-to-charge ratio. RESULTS: Of the 1405 cases of abuse by a spouse or partner identified, 94% were female and 61% were admitted via the emergency room. The mean age was 40 years (range: 16-101). The average length of stay (LOS) was 4 days (range: 1-96) and the hospital case fatality rate was 1%. The mean cost per stay was $6,820 (range: $298- $349,983). Among those discharged, 83% went home; 5% of them with home health care services. Another 10% required further care in a rehabilitation, skilled nursing or intermediate care facility. The remainder either signed out against medical advice, were discharged to another type of facility (e.g., mental health facility, residential care) or the disposition status was unknown. The total cost for hospital care over the 4 years for these spouse/partner abuse cases was estimated at $10.1 million, roughly $2.5 million annually. CONCLUSIONS: The overwhelming majority of hospitalizations resulting from spousal or partner abuse are for women and most patients return home after hospitalization. While a hospital stay is only one level of management for this type of abuse, it represents a substantial cost and should be incorporated into any analysis that examines the economic impact of spousal/partner abuse.