To evaluate the design, development, and implementation of Florida's Medicaid provider service network (PSN) demonstration, and the implications of that demonstration for subsequent Medicaid Reform in Florida. DATA SOURCES, DATA COLLECTION: Organizational analyses were based on archival and enrollment data obtained from Florida's Medicaid program and the South Florida Community Care Network, as well as key informant interviews. Closely related fiscal analyses utilized Medicaid claims data from March 1999 through October 2001 extracted from the Florida Medicaid Management Information System. The organizational analyses reported here were based on a structured case study research design. Almost every aspect of the development of the new organizational form (PSN) took longer and was more difficult than anticipated. Prior organizational experience with insurance functions proved to be an asset. While fiscal analyses indicated that the program saved the state of Florida a significant amount of money, tracking the precise origin of the savings proved to be challenging. By most standards, the PSN program was observed to meet its stated objectives. Based in part on this conclusion, the state chose to extend the use of PSNs within its 2006 Medicaid Reform initiative.