This paper describes the development of a remote physiological monitoring (RPM) system named e-Guardian for the elderly living alone or patients having chronic diseases. e-Guardian is a home-based e-monitoring and notification system which is low-cost, small, extremely power saving, simple in design and operation, and robust in performance. The centerpieces of e-Guardian are wearable devices which are capable of measuring blood pressure, monitoring heart rate, detecting accidental falls, tracking location, etc. e-Guardian adopts a modular design approach so that users have freedom to fit desired sensor modules to it. It communicates via ZigBee mesh network with the Base Station which is integrated to a GSM module. Vital signs and health status are sent in real time to caregivers' mobile phones in human readable SMS format. Meanwhile, caregivers are able to query the users' status and initiate simple diagnosis via only SMS commands in case of emergency.