Background: During the years 1987-1991, a statewide trauma system was implemented in Oregon (Ore) but not in Washington (Wash), Incidence of hospitalization, frequency of death and risk-adjusted odds of death for injured children (< 19 years) in the two adjacent states were compared for two time periods (1985-1987 and 1991-1993), Methods: State populations of injured children (International Classification of Diseases, 9th Revision - Clinical Modification, code 800-959) were identified through a Hospital Discharge Index, Hospitals in counties with a population density < 50 persons/square mile were designated rural, Incidence rates are events/10,000 pediatric population per year, Results: The pediatric population increased in both states (Ore: 687,000-758,000; Wash:1,159,000-1,336,000). Incidence of hospitalization for all injured children in entire states declined (Ore: 66.5-38.5; Wash:54-33); also in rural hospitals (Ore: 67.5-32; Wash: 48 to 31), Seriously injured children (score on the Injury Severity Scale > 15) had a lower incidence in 1991-1993 of admission to rural hospitals (Ore: 2.98; Wash: 2.82) compared with incidence for entire states (Ore: 4.61; Wash: 4.62); in 1985-1987 the incidence was not different, Furthermore risk adjusted odds of death for seriously injured children was significantly lower in Oregon than in Washington in the later time period, Conclusion: Both states show a similar temporal trend toward a declining frequency of death for children hospitalized with injuries, Injury prevention strategies appear to have reduced the number of serious injuries in both states, However, seriously injured children demonstrated a reduced risk of death in Oregon, consistent with benefit from a statewide trauma system.