A diagnosis system, a medical image system, and a method of displaying a diagnosis image are provided. The diagnosis system includes a probe including a plurality of sub-arrays, each of the sub-arrays including at least one line of array transducers, the array transducers being configured to transmit and receive signals to and from a subject being diagnosed, and a hybrid beamformer configured to perform analog beamforming in a direction in which the sub-arrays are arranged, and perform digital beamforming in a direction perpendicular to the direction in which the sub-arrays are arranged.