This paper traces the development of the regionalization of health care services to the present model of the Health Systems Agency, HSA. Survey data obtained by a mailed questionnaire sent to hospital administrators is presented. The focus of the presentation is on a number of organizational variables as they influence the hospital administrator's perception of the necessity and effectiveness of the HSA. Organizational variables examined include the profit-nonprofit dimension; the location of the hospital, urban versus rural; organizational size as measured by three different criteria; and organizational age. Fifty questionnaires were mailed. Twenty-six questionnaires were returned, yielding a response rate of 52%. The findings are viewed as largely exploratory. Support for the HSA model among hospital administrators does not appear to be enthusiastic. Among those administrators who viewed the HSA as necessary, the model response was that the HSA's would be somewhat beneficial. Of all the variables examined, age of hospital seemed to be the most crucial in predicting support of the HSA. (Author/AM)