Based on organization theory and the work of Roemer and Friedman, seven dimensions of hospital medical staff organization structure are proposed and examined. The data are based on a 1973 nationwide survey of hospital medical staffs conducted by the American Hospital Association. Factor analysis yielded six relatively independent dimensions supporting a multidimensional view of medical staff organization structure. The six dimensions include 1) Resource Capability, 2) Generalist Physician Contractual Orientation, 3) Communication/Control, 4) Local Staff Orientation, 5) Participation in Decision Making, and 6) Hospital-Based Physician Contractual Orientation. It is suggested that these dimensions can be used to develop an empirical typology of hospital medical staff organization structure and to investigate the relationship between medical staff organization and public policy issues related to cost containment and quality assurance.