Osteogenesis imperfecta (OI), a rare connective tissue deformity, can be classified into four categories, one of which (type II) is lethal. Lethal OI can be detected with the use of ultrasound prenatally. The authors studied nine OI cases, seven type II OI cases, and two nonlethal cases. All seven type II OI cases had very short limbs. In six of the seven cases, the back wall of the limb bone was visible (transparent bone sign). In four of the seven cases, concave ribs were visualized in the transverse plane. An incidental finding, beaking of the anterior portion of the skull, was noted in five cases. The transparent bone sign and concave ribs were not observed in the two nonlethal cases of OI.