Public outcry regarding unsafe interhospital patient transfers led to the passage of the COBRA Law of 1985. Since its implementation in 1986, the law has been sharply criticized for its sporadic enforcement, narrow focus, and lack of care provisions for the poor. We reviewed retrospectively the charts of all emergency department patients transferred from two Milwaukee private hospitals during two identical 6-month periods in 1985-1986 and 1988-1989. We compared demographic and clinical characteristics of the patients transferred during the two periods. The emergency departments cared for 15% of Milwaukee's emergency patient population and transferred 216 and 200 patients during each respective period. Uninsured transfers fell from 32% to 17% of the study populations. Although the proportion of the local population belonging to a health maintenance organization (HMO) did not change, transfer of HMO patients increased from 14% to 27%. Transfers to the area's various tertiary care centers made up 21% and 35% of all transfers and were conducted without regard to insurance status. There was a fourfold increase in the use of the county's public assistance plan for emergency hospitalization of indigent patients at local hospitals. Although the number of uninsured patients transferred from the study hospitals decreased markedly, this decrease was counterbalanced by increased private hospital use of the county's emergency hospitalization plan for indigent patients. This successful plan bears further examination by health policy planners as an important model for the provision of emergency hospitalization for the indigent.