In the field of medical image processing, one of the cur- rent interests is the automatic segmentation of abdominal CT images, which is the first and fundamental step both be- fore any automatic pathology detection and to compute the 3D abdominal organ volumes. In this paper we propose our fully automatic system that segments liver and its blood ves- sels, kidneys, spleen, ribs and spine. The overall system has been evaluated on the data of 40 patients, obtaining a good assessment both by visual inspection by three experts, and by comparing the computed results to the manually traced boundaries.