Abstract: A method of and a system for development of health care information Systems (HIS) are disclosed. The method includes providing software programming interfaces for development of application modules, communication interfaces for establishing communication between various modules, and resource management interfaces for allocation of resources such as memory. The system comprises of a server with a health care middleware operating system (HMOS). The HMOS is designed as a multi-tier architecture with 3 tiers namely, application tier, domain services tier, and Foundations tier.