AdjudiPro, version 2.0, is the latest incarnation of United HealthCare’s patented physician claims adjudication expert system (US patent # 5,359,509). Its core is an embedded expert system that contains the logic for processing 55% of all physician claim situations reviewed on United HealthCare’s managed care system. Certain physician services are reviewed as part of the claims adjudication process to ensure that submitted charges meet contractual, and other guidelines. In 1995, nearly $20 million in gross savings was realized through use of this system. Since its initial deployment in 1991-1992, there has been a steep increase in AdjudiPro’s processing volume. This increased demand created a number of issues that had to be addressed to ensure AdjudiPro’s continued viability and growth. As a result, much of the past three years was spent rearchitecting AdjudiPro to meet the increasing load placed on it, while achieving acceptable throughput. AdjudiPro is now an essentially real-time application, processing claims twenty-four hours a day, seven days a week. This paper describes the current AdjudiPro application, and the key issues faced during the past three years.