A brief overview of fiber Bragg grating based sensor technology from sensor head, read out unit and commercial applications is given. Fiber Bragg grating based sensor systems are becoming mature rapidly. Components for commercial pressure sensors and temperature sensors are available and slowly getting accepted. However, many advantages of the fiber Bragg grating as sensor are still not fully recognized by a wider audience. Properties such as the ability for distributed sensing, small size, light weight, immune for electromagnetic interference and resistance to harsh environments are examples of the advantages of fiber Bragg grating based sensors.