Health Care System is a data intensive industry so it can highly benefit from information technology system. In the last few years different parts of Health Care System especially hospitals tried to use information technology as their information management system. Today in many Iranian hospitals different kinds of Hospital Information Systems are employed for managing ADT, Lab data, and pharmacy and so on. Unfortunately many of these systems were developed by local companies for special needs of specific hospitals or department, so they are not compatible and interoperability with each other. To overcome this problem our HIS team in MUMS is using HL7 standards for developing different components of system.