The issue of loss or kidnapping children has become unfortunately a widespread phenomenon in many countries. To address this issue, this paper presents a children tracking system. It consists of a small device carried by the child and a mobile application that enables the user to track his child movements by tracking that device. That will be done by using GPS and Bluetooth 4.0 technology to track children in indoor and outdoor locations. For indoor, the application searches for the child by detecting the beacon device using Bluetooth 4.0. And for the outdoor locations, the application uses the GPS/GPRS chip.