Intimate partner violence (IPV) is a serious public health problem in the United States and a common cause of injury. Prevalence rates of IPV vary by the surveillance methods and definitions used. National data from the 1995 National Violence Against Women Survey indicate that 22.1% of women and 7.4% of men experience IPV during their lifetimes and that 1.3% of women and 0.9% of men experience IPV annually. IPV results in an estimated 4.1 billion dollars each year in direct medical and mental health-care costs, including 159 million dollars in emergency department (ED) treatments for IPV physical assaults. IPV might constitute as much as 17% of all violence-related injuries treated in EDs. To determine the magnitude of the IPV problem in Oklahoma, including IPV-related injuries and medical service utilization, researchers analyzed injury surveillance data from ED medical records and data from the Oklahoma Women's Health Survey (OWHS). This report summarizes the findings, which indicated that, during 2002 in Oklahoma, approximately 16% of all ED visits for assaults were for IPV injuries, including 35% of assault visits among females and 3% of assault visits among males. In addition, results of the OWHS for 2001-2003 indicated that 5.9% of surveyed Oklahoma women aged 18-44 years sustained an IPV injury during the preceding year. Overall, IPV resulted in a substantial number of injuries, particularly to women, many of whom required treatment in EDs. Medical recognition and documentation of IPV are important for identification of persons in need of services.