A distributed monitoring system has been developed, which is organized with network cameras, an integrated web/mail server, web-based clients including high-performance cellular phones, remote sensors, remote switches and remote control devices. The integrated web/mail server is designed to play intensive roles to obtain images and data from network cameras and remote sensors respectively, process them, accumulate them into its simple database, receive requests from clients, and perform several kinds of services for monitoring and/or controlling. Almost software of our distributed controlling system has been written in Java programming language, because of easy and powerful description of GUI and network programming as well as independency of execution environment. KEYWORDS Remote monitoring and controlling, Java technology for server-client computing, Web-based applications