Abstract: Image segmentation is an elementary problem in computer vision and plays very important role in various image application domains.. Regardless of years of research in the area of general purpose image segmentation, it is still a very challenging task since it is inherently ill-posed. Out of different segmentation schemes available today, graph theory based techniques have several excellent characteristics in practical applications. Such graph theory based image segmentation techniques explicitly organize the image objects into mathematically structures, making the computation of image segmentation problem more flexible and efficient. This research work basically employs fundamental concepts of histogram and graph theory for image segmentation. The PSNR and time taken for image segmentation has been used as a comparison parameter for proposed image segmentation methods.