Liver segmentation from Computed Tomography (CT) is a significant but challenging task. In the abdominal CT scan image the liver is seen clearly nevertheless the physician needs the accurate boundaries and correct size measurement for the liver transplantation surgery. The boundaries of the various organs are nor clearly visible as a result of complex structure of the human body. This paper presents an efficient and fully automated liver segmentation technique. The proposed method uses Ant Colony Optimization technique alongside k-means and Level set to locate the liver region.