The present invention relates to an ultrasound imaging system. The ultrasound imaging system includes an ultrasound diagnostic unit and an image processing unit. The ultrasound diagnostic unit transmits ultrasound signals to a target object and forms receive data based on ultrasound echo signals reflected from the target object. The image processing unit forms an ultrasound image based on the receive data. The image processing unit includes a graphic processing unit configured to perform at least one of functions including processing the receive data to form image data, performing scan conversion upon the image data to form scan-converted data suitable for display, and rendering and filtering the scan-converted data to form pixel data.