This streetlight monitoring system is aimed at preventing unnecessary energy wastage by applying the GSM (Global System for Mobile Communications) technology. This system consists of two parts: the monitoring centre and the terminal nodes. The Siemens TC35 GSM module is used to send and receive short messages and it is installed in the monitoring centre and each streetlight. ATmega168 is used to determine whether or not it is necessary for the streetlights to be turned on, and then it executes commands from the control centre. When the sky is bright enough for drivers, the streetlights will automatically turn off. Also, if some streetlights are broken down, the TC35 GSM module will send an alarm short message to the monitoring centre and maintenance personnel will repair the lights as soon as possible. Thus, maintenance personnel will no longer have to make time-consuming visits to check up on the function status of every streetlight. All information is presented in the monitoring computer which is programmed in LabVIEW. The workman can easily turn on or off any streetlight by clicking on the screen.