A 3-dimensional (3D) ultrasound apparatus and a method for operating the same are provided. A 3D ultrasound apparatus includes a first processor, a second processor and a controller. The first processor determines a start point from an image data obtained by scanning an object in a human body. The second processor extracts a top image of the object from the image data based on the start point. The controller controls a sagittal view of the object by rotating the image data, using the top image.