With the aging of the population, health-care is one of the fastest growing industries in Taiwan as well as in many other countries. A smart home-monitoring application based on a ZigBee sensor network was developed and implemented to enable the physician and the caregiver to access patient data so that they can respond instantly to any irregularity in the condition of in-home patients. The proposed system includes a system simulator, medical instrument definition module and network monitor module. System functions include network parameter settings, real-time system status sensing and data collection, intelligent event tracing and warning, and ad hoc response mechanisms. The aim of this study is to give both patient and caregivers better control of health care.