Abstract. We present a new method for delineating the osseous interface in ultrasound images. Automatic segmentation of the bone-soft tissues interface is achieved by mimicking the reasoning of the expert in charge of the manual segmentation. Information are modeled and fused by the use of fuzzy logic and the accurate delineation is then performed by using general a priori knowledge about osseous interface and ultrasound imaging physics. Results of the automatic segmentation are compared with the manual segmentation of an expert.