Health care systems are under pressure to adopt contemporary management practices including activity based costing (ABC). This paper reports an intensive case study of the design of an ABC system in a newly organized public foundation hospital in Spain. The study covered a few years and was based on interviews, observations, and extensive review of documentation.   The analysis draws on an institutional sociology framework .  A primary finding is that there was no conflict between physicians and administration, unlike the previous wisdom that such conflict is inherent in ABC implementation. Training medical personnel in management and involving them in management, as well as educating implementers in medical issues represented major reasons for no conflict. Although no generalizable outside this specific context, it provides the basis for broader empirical research.