Computer vision-based gender detection from facial image is a challenging and important task for computer vision-based researchers. The automatic gender detection from face image has potential applications in visual surveillance and human-computer interaction sys- tems (HCI). Human faces provide important visual information for gender perception. The system described in this book can automatically detect face from input images and the detected facial area is taken as region of interest (ROI). Some techniques and algorithm of Image Processing is applied on that ROI which identifies the gender of the face image.The experimental reseult described on chapter 4 in this book finds the accuracy of the system is more than 80%.